Stadler Flirt And Bombardier Aventra Tri-Modes Compared
In this post, I will assume that a tri-mode train is capable of the following.
- Running using 25 KVAC overhead and/or 750 VDC third-rail electrification.
- Running using an on-board power source, such as diesel, hydrogen or Aunt Esme’s extra-strong knicker elastic.
- Running using stored energy for a reasonable distance.
I would suggest that a reasonable distance for battery power would include routes such as.
- Northallerton – Middlesbrough
- Ashford – Hastings
- Lancaster – Barrow
- Preston – Burnley
Preferably, the trains should be able to go out and back.
The Stadler Flirt Tri-Mode
What we know about the Stadler Flirt Tri-Mode has been pieced together from various sources.
The tri-mode trains for South Wales and the Class 755 trains for East Anglia use the same picture as I pointed out in Every Pair Of Pictures Tell A Story.
This leads me to surmise that the two trains are based on the same basic train.
- Three or four passenger cars.
- A power-pack in the middle with up to four Deutz 16 litre V8 diesel engines.
- 25 KVAC overhead electrification capability.
- 100 mph operating speed.
This is a visualisation of the formation of the trains clipped from Wikipedia.
One of the routes, on which Greater Anglia will be using the trains will be between Lowestoft and Liverpool Street, which shows the versatility of these trains.
They will be equally at home on the rural East Suffolk Line with its numerous stops and 55 mph operating speed, as on the Great Eastern Main Line with its 100 mph operating speed.
South of Ipswich, the diesel engines will be passengers, except for when the catenary gets damaged.
In Tri-Mode Stadler Flirts, I said this.
I would expect that these trains are very similar to the bi-mode Stadler Flirt DEMUs, but that the power-pack would also contain a battery.
As an Electrical and Control Engineer, I wouldn’t be surprised that the power-pack, which accepts up to four Deutz diesel engines, can replace one or two of these with battery modules. This could make conversion between the two types of Flirt, just a matter of swapping a diesel module for a battery one or vice-versa.
Note that the three-car Class 755 trains for Greater Anglia have two diesel engines and the four-car trains have four engines.
In the July 2018 Edition of Modern Railways, there is an article entitled KeolisAmey Wins Welsh Franchise.
This is said about the Stadler Tri-Mode Flirts on the South Wales Metro.
The units will be able to run for 40 miles between charging, thanks to their three large batteries.
So could it be that the tri-mode Stadler Flirts have three batteries and just one diesel engine in the four slots in the power-pack in the middle of the train?
The Bombardier High Speed Bi-Mode Aventra
In the July 2018 Edition of Modern Railways, there is an article entitled Bi-Mode Aventra Details Revealed.
As is typical with Bombardier interviews, they give their objectives, rather than how they aim to achieve them.
In Bombardier Bi-Mode Aventra To Feature Battery Power, I said this.
The title of this post is the same as this article in Rail Magazine.
A few points from the article.
- Development has already started.
- Battery power could be used for Last-Mile applications.
- The bi-mode would have a maximum speed of 125 mph under both electric and diesel power.
- The trains will be built at Derby.
- Bombardier’s spokesman said that the ambience will be better, than other bi-modes.
- Export of trains is a possibility.
Bombardier’s spokesman also said, that they have offered the train to three new franchises. East Midlands, West Coast Partnership and CrossCountry.
Very little more can be gleaned from the later Modern Railways article.
Good Customer Feedback
Would they say anything else?
But Bombardier have claimed in several articles, that the Aventra has been designed in response to what operators and passengers want.
Performance
The Modern Railways article gives this quote from Des McKeon of Bombardier.
From the start we wanted to create a bi-mode which would tick all the boxes for the Department of Transport and bidders.
That means a true 125 mph top speed and acceleration which is equally good in both electric and diesel modes. We have come up with a cracking design which meets these criteria.
I also think it is reasonable to assume that the performance of the proposed trains is very similar or better to that of Bombardier’s Class 222 train, which currently run on the Midland Main Line.
After all, you won’t want times between London and the East Midlands to be longer.
Distributed Power
Distributed power is confirmed in the Modern Railways article, by this statwment from Des McKeon of Bombardier.
The concept involves underfloor diesel engines using distributed power.
But distributed power is inherent in the Aventra design with the Class 345 trains.
I found this snippet on the Internet which gives the formation of the nine-car trains.
When operating as nine-car trains, the Class 345 trains will have two Driving Motor Standard Opens (DMSO), two Pantograph Motor Standard Opens (PMSO), four Motor Standard Opens (MSO) and one Trailer Standard Open (TSO). They will be formed as DMSO+PMSO+MSO+MSO+TSO+MSO+MSO+PMSO+DMSO.
Eight cars are motored and only one is a trailer.
The snippet has a date of August 13th, 2016, so it could be out of date.
It would also appear that the Class 720 trains for Greater Anglia, which are built to cruise at 100 mph, do not have any trailer cars.
It will be interesting to observe the formation of the Class 710 trains, when they start running in the autumn.
Surely to have all these traction motors in each car must be expensive, but it must give advantages.
Perhaps, each motored car has a battery to handle the regenerative braking. This would minimise the power passed between cars, which must be energy efficient for a start.
Consider the following.
- An MS1 car for a Class 345 train weighs 36.47 tonnes.
- A typical car can accommodate a total of about 175 seated and standing passengers.
- With bags, buggies and other things passengers bring on, let’s assume an average passenger weight of 90 kg, this gives an extra 15.75 tonnes.
- Suppose the battery were to weigh a tonne
- So I will assume that an in service MS1 car weighs 53.2 tonnes.
Calculating the kinetic energy of the car for various speeds gives.
- 75 mph – 8.3 kWh
- 90 mph – 12 kWh
- 100 mph – 14.8 kWh
- 125 mph – 23 kWh
Considering that the Bombardier Primove 50 kWh battery, which is built to power trams and trains, has the following characteristics.
- A weight of under a tonne.
- Dimensions of under two x one x half metres.
- The height is the smallest dimension, which must help installation under the train floor or on the roof.
I don’t think Bombardier would have trouble finding a battery to handle the regenerative braking for each car and fit it somewhere convenient in the car.
Underneath would be my position, as it is closest to the traction motors.
So just as traction is distributed, could the batteries and diesel power be distributed along the train.
Underfloor Diesel Engines
The full statement about what Des McKeon said, that I used earlier is as follows.
The concept involves underfloor diesel engines using distributed power, but that designing from scratch enabled Bombardier to fit these without having to substantially raise the saloon floor height on any of the vehicles.
When asked about which diesel engines would be used, Mr. McKeon also confirmed that there were at least two potential suppliers, and that the diesel engines fitted would comply with the latest and highest emissions standards.
Conversion to pure electric operation is also a key design feature, with the ability to remove the diesel engines and fuel tanks at a later date, if they were no longer required.
One of my customers fror data analysis software, was Cummins, who have supplied Bombardier with diesel engines in the past. One thing that impressed me, was that they have an ability to reposition all the ancillaries on a diesel engine, so that, if required for a particular application, it could be fitted into a confined space.
I believe from what I saw, that Cummins or one of the other diesel engine manufacturers could supply a low-height diesel engine with an adequate power level to fit under the car floor without raising it by an unacceptable amount.
If you travel on one of London’s New Routemaster buses and sit in the back seat downstairs, at times you can just about hear the diesel engine, which is placed under and halfway-up the stairs, as it starts and stops. But generally, the engine isn’t audible.
A typical Volvo double-decker bus like a B5TL, is powered by a 5.1 litre D5K-240 engine, which is rated at 240 bhp/177 kW.
By contrast, the New Routemaster is powered by a Cummins ISBe engine with a capacity of 4.5 litres and a rating of 185 bhp/138 kW. One of the major uses of a larger 5.9 litre version of this engine is in a Dodge Ram pickup.
The two buses do a similar job, but the New Routemaster uses twenty percent less power.
The saving is probably explained because the New Routemaster is effectively a battery bus with regenerative braking and a diesel engine to charge the battery.
I am led to the conclusion, that Bombardier plan to fit an appropriately sized diesel engine under the floor of each car in the train.
Bombardier built the 125 mph Class 222 train, which have a 19-litre Cummins QSK19 engine rated at 750 bhp/560 kW, in each car of the train. I can’t find the weight of a car of a Class 222 train, but that for a similar 220 train is around 46.4 tonne, of which 1.9 tonnes is the diesel engine.
Applying the same logic, I can calculate the energy for a single-car of a Class 222 train.
- A typical car weighs 46.4 tonnes.
- A typical car can accommodate a total of about 75 seated and standing passengers.
- With bags, buggies and other things passengers bring on, let’s assume an average passenger weight of 90 kg, this gives an extra 6.75 tonnes.
- So I will assume that an in service car weighs 53.2 tonnes.
Remarkably, the weight of the two cars is the same. But then the Aventra has more passengers and a heavy battery and the Class 22 train has a heavy diesel engine.
As both trains have the same FLexx-Eco bogies, perhaps the car weight is determined by the optimum weight the bogies can carry.
Calculating the kinetic energy of the car for various speeds gives, these figures for a single car of a Class 222 train.
- 75 mph – 8.3 kWh
- 90 mph – 12 kWh
- 100 mph – 14.8 kWh
- 125 mph – 23 kWh
I will also adjust the figures for the proposed high speed bi-mode Aventra, by adding an extra tonne to the weight for the diesel engine and fuel tank.
This gives the following figures for a tri-mode 125 mph Aeventra.
- 75 mph – 8.5 kWh
- 90 mph – 12.1 kWh
- 100 mph – 15 kWh
- 125 mph – 23.5 kWh
Note that increase in speed is much more significant, than any increase in weight of the car, in determining the car energy.
I will now look at how the high speed bi-mode Aventra and a Class 222 train, running at 125 mph call at a station and then accelerate back to this speed after completing the stop.
The high speed bi-mode Aventra will convert the 23.5 kWh to electrical energy and store it in the battery.
After the stop, probably eighty percent of this braking energy could be used to accelerate the train. I m assuming the eighty percent figure, as regenerative braking never recovers all the braking energy.
This would mean that to get back to 125 mph, another 5.1 kWh would need to be supplied by the diesel engine.
In contrast the diesel engine in the car of the Class 222 train would need to supply the whole 23 kWh.
As the time to accelerate both trains to 125 mph will be the same, if Bombardier are to meet their probable objective of similar performance between the following.
- Bi-mode Aventra in electric mode
- Bi-mode Aventra in diesel mode.
- Class 222 train.
This means that the size of diesel engine required in the bi-mode Aventra’s diesel in each car is given by.
560 * 5.1/23 = 124 kW or 166 bhp.
The quiet Cummins ISBe engine with a capacity of 4.5 litres and a rating of 185 bhp/138 kW from a New Routemaster bus, would probably fit the bill
Could we really be seeing a 125 mph bi-mode train powered by a posse of Amrican pick-up truck engines?
The mathematics say it is possible.
If you think, I’m wrong feel free to check my calculations!
Last Mile Operation
The Modern Railways article, also says this about last mile operation.
The option for last-mile operation or for using this technology through short sections, such as stations will also be available, although Mr. McKeon said this is not in the core design.
I think there is more to this than than in the words.
The South Wales Metro is making extensive use of discontinuous electrification to avoid the need to raise bridges and other structures. I said more in More On Discontinuous Electrification In South Wales.
The ability to run on a few hundred metres of overhead rail or wire, without any power would be very useful and allow electrification to be simplified.
Imagine too a section of line through a Listed station or historic landscape, where electrification would be difficult for heritage reasons.
The train might glide silently through on battery power, after lowering the pantograph automatically. It would raise automatically, when the electrification was reached on the other side.
And then there’s all the depot and stabling advantages, of using batterry power to cut the amount of electrification and improve safety.
Future Fuels
The Modern Railways article, also says this about future fuels.
Mr McKeon said his view was that the diesel engines will be required for many years, as other power sources do not yet have the required power or efficiency to support inter-city operation at high speeds.
Running at high speeds in itself is not the problem, as a train with good aerodynamics and running gear will run easily without too many losses due to friction.
The biggest use of traction energy will be accelerating the train up to operating speed after each stop.
It is too early yet to judge whether fuels like hydrogen will be successful, but other areas will improve and make trains more efficient.
- Improved aerodynamics.
- Better traction motors.
- Better batteries with a higher energy storage per kilogram of battery weight.
- More efficient, quieter and less polluting diesel engines.
- More intelligent control systems for the train and to inform and assist the driver.
I also think there is scope for electrifying sections of track, where energy use is high.
Interior And Passenger Comfort
The Modern Railways article finishes with this paragraph.
In terms of the interior, Mr. Mckeon said the aim was to offer passenger comfort to match that on an EMU. The key elements of this are to have less vibration, less noise and an even floor throughout the passenger interior.
I believe my calculations have shown that using batteries to handle regenerative braking, substantially reduces the size of the diesel engines required, to about that of those in a serial hybrid bus, like a New Routemaster.
These smaller engines are much quieter, with much less noise and vibration.Their smaller size will also make designing a train with a uniform even floor a lot easier.
Comparing The Two Trains
Operating Speed
The maximum operating speed of the two trains is as follows.
- Tri-Mode Stadler Flirt – 100 mph
- High Speed Bi-Mode Aventra – 125 mph
This would appear to be a point to Bombardier. But could the speed of the tri-mode Stadler Flirt be increased?
125 mph Flirt EMUs do exist, but these don’t have the power pack in the middle, which may have the capability to introduce unwelcome dynamics into the train.
On the other hand, the high speed bi-mode Aventra, is dynamically at least, very much a conventional non-tilting high speed train., even if the way the train is powered is unconventional.
UK high speed trains have generally been capable of greater than 125 mph.
- The InterCity 125 set the world record for a diesel train at 148 mph, on the first of November 1987.
- The InterCity 225 was designed to run at 140 mph (225 kph) with in-cab signalling. In 1989, one train achieved 161 mph.
- Class 395 trains regularly run at 140 mph on HS1 and have run at 157 mph.
- Class 800, Class 801 and Class 802 trains are all designed to run at 140 mph with in-cab signalling.
I can’t help thinking that Bombardier’s engineers know a way of obtaining 140 mph out of their creation.
Calculation shows that the kinetic energy of one car of a high speed bi-mode Aventra travelling at 140 mph is 30 kWh, which is still easy to handle, in a train with a battery and a diesel engine in each car.
Could this train be the ideal classic-compatible train for High Speed 2?
Battery Range
I said earlier that the range of the Tri-Mode Stadler Flirt will be forty miles on batteries.
So how far will Bombardier’s high speed bi-mode Aventra go on full batteries?10 and 17
I speculated that these trains are formed of cars with a 50 kWh battery and a small diesel engine of about 124 kW in each car.
In an article in the October 2017 Edition of Modern Railways, which is entitled Celling England By The Pound, Ian Walmsley says this in relation to trains running on the Uckfield Branch, which is not very challenging.
A modern EMU needs between 3 and 5 kWh per vehicle mile for this sort of service.
So the range could be somewhere between 10 and 17 miles.
But the more efficient the train, the greater the distance.
Reducing energy consumption to 2 kWh per vehicle mile would give a range of 25 miles.
Adding More Cars
Adding more cars to an Aventra appears to be fairly easy, as these trains can certainly be ten-car units.
But doing this to a Tri-Mode Stadler Flirt may be more difficult due to the train’s design. Five or possibly six cars might be the limit.
Routes For Bombardier’s 125 Mph Bi-Mode Aventra
This article in Rail Magazine, is entitled Bombardier Bi-Mode Aventra To Feature Battery Power.
A few points from the article.
- Development has already started.
- Battery power could be used for Last-Mile applications.
- The bi-mode would have a maximum speed of 125 mph under both electric and diesel power.
- The trains will be built at Derby.
- Bombardier’s spokesman said that the ambience will be better, than other bi-modes.
- Export of trains is a possibility.
Bombardier’s spokesman also said, that they have offered the train to three new franchises. East Midlands, West Coast Partnership and CrossCountry.
These are my thoughts on these franchises.
Bi-Mode And Pure Electric
I’m pretty certain that if you want to create a 125 mph bi-mode train, you start with a 125 mph electric train, if you want a high degree of commonality between the two trains.
Hitachi have a whole family of Class 800 trains, each of which has a different specification for the diesel power. Even the pure-electric Class 801 trains, has one diesel engine for emergencies.
An electric train with batteries could be very efficient, if the batteries were used to handle regenerative braking and boost the trains, where more power is required.
East Midlands
It is no surprise that Bombardier are talking to the groups, that are bidding to become the new franchise holder for the East Nidlands, when it is awarded in April 2019.
They wouldn’t want to see another company’s product roaring past the factory.
The proposed bi-mode Aventra will probably have been designed very much with the Midland Main Line in mind.
- The Midland Main Line will be electrified from St. Pancras to Kettering and Corby.
- Will the fast lines be electrified to Glendon Junction, where the Corby Branch joins the Midland Main Line?
- The route between St. Pancras and Glendon Junction is being upgraded to four tracks, with as much 125 mph running as possible.
- The non-stop nature of Midland Main Line services South of Kettering could be significant.
- North of Kettering, there is currently no electrification.
- The development of Toton station for HS2 is being accelerated and there could be an island of electrification here, by the mid-2020s.
- If HS2 shares the Midland Main Line corridor between Toton and Sheffield, this section could be electrified by the late-2020s.
Over the next decade, there will be more electrification and a greater proportion of the route, where 125 mph running will be possible.
There has been a bit of controversy, that the number of stops the franchise will make at Bedford and Luton is being reduced after May this year.
The reason given is that it will enable faster services to Derby, Nottingham and Sheffield.
North To Derby, Nottingham and Sheffield
Consider a bi-mode train with batteries going North.
- Between St. Pancras and Kettering, it will be at 125 mph for as long as possible.
- The train will also ensure that at Kettering, it has the batteries brim full, sfter charging from the electrification.
- After a stop at Kettering station, if the electrification reached to Glendon Junction, the acceleration would all be electrically-powered.
- Whether it stopped at Kettering or not, the train would pass Glendon Junction at line speed with full batteries.
It’s almost as if the electrification is being used as a catapult to speed the train North.
South From Derby, Nottingham and Sheffield
Being as electrically efficient coming South would be a lot more difficult.
- I suspect that train batteries will be charged at Derby, Nottingham and Sheffield, so they start their journey South with full batteries.
- Using a full battery and assistance from the onboard generator, trains would be accelerated away from the terminii.
- The trains computer would select automatically, whether to use battery or onboard generator power and would harvest all the power from regenerative braking.
- At each stop on the journey, energy would be lost, as regenerative braking systems do not are only between seventy and ninety percent efficient.
- Once at Glendon Junction, the train would raise the pantograph and switch to getting power from the overhead wires.
It’s all about a well-programmed computer on the train, which knows the route, the timetable and battery state so it can switch power sources appropriately.
Electrification
On the other hand, electrification around Toton could make everything easier and more efficient.
With electrification, every little helps.
- Modern trains can raise and lower pantographs, quickly and automatically.
- Faster journeys.
- Lower carbon emissions.
- Less noise and vibration from diesel generators.
Everyone’s a winner.
Oakham To Kettering
The Oakham-Kettering Line to Corby station is being electrified, double-tracked and I suspect speed limits will be raised.
Speed limits are also being raised and track improvements are being done, South of Glendon Junction.
Currently, services take seventy minutes. With the 125 mph Aventras on the route, they will not need to use the onboard generator, but surely the journey time could be reduced to under an hour, which would attract passengers and need less trains to run a two trains per hour (tph) service.
The Oakham Problem
Oakham station is in the middle of the town, as this Google Map shows.
The Department for transport would like to see more services to the town and the next station of Melton Mowbray.
But the line through the station is busy with freight trains and there is a level crossing in the middle of the town.
125 mph bi-mode trains, won’t help with the problem of Oakham.
Joining And Splitting Of Trains
There is also the possibility of joining and splitting trains.
Hitachi’s Class 800 trains can do this and I’m sure bi-mode Aventras will be able to do this automatically.
There is only four platforms available for trains on the Midland Main Line at St. Pancras and regularly two trains occupy one platform.
The ability to run a pair of bi-mode trains, that joined and split could be a great asset.
Liverpool To Norwich
This long route is an important one for those, who live near its stations. It is usually served by one or two Class 158 trains, which are often very crowded.
The route is partially electrified.
- Liverpool to Hunts Cross
- Manchester Oxford Road to Stockport
- Grantham to Peterborough
- Around Ely
- Around Norwich
So there should be plenty of places to raise the pantograph and charge the batteries.
It is a typical long-distance route for the UK and I’m sure it would benefit from 125 mph bi-mode Aventras.
West Coast Partnership
Bids for the West Coast Partnership, which will run services on the West Coast Main Line and HS2, will be submitted by July 2018. The winning bidder will be announced in May 2019 and take over services two months later.
A modern 125 mph bi-mode would be an ideal replacement for the current twenty Class 221 trains, that work on the West Coast Main Line.
These Class 221 trains are.
- Diesel powered.
- Five-cars long.
- Built in 2001-2002 by Bombardier.
- 125 mph capable.
- Some services are run by splitting and joining trains.
But most importantly, most services are run substantially under wires.
New 125 mph bi-mode trains would certainly improve services.
- Several of the current services operated by Class 221 trains, would become electric ones.
- How much faster would they be able to run a service between London Euston and Holyhead?
- They would also be able to run new services to places like Barrow. Blackburn and Huddersfield.
- Five cars could be a convenient train size for the operator.
But above all, they would offer a better passenger experience, with less noise and vibration from the diesel engines.
The longest section of running using onboard power of a bi-mode Aventra will be along the North Wales Coast Line to Holyhead.
- The line has an 90 mph operating speed.
- The line is 85 miles long.
- The gradients won’t be too challenging, as the line runs along the coast.
- Services stop up to half-a-dozen times on the route.
- From London to Crewe is electrified.
- The section between Crewe and Chester may be electrified.
It looks to be an ideal route for a 125 mph bi-mode Aventra.
As the route appears to not be as challenging as the Midland Main Line, could this route, be the ideal test route for a hydrogen fuel-cell powered Aventra.
West Coast Partnership may well have plans to use 125 mph bi-mode trains as feeder services for HS2’s hubs at Birmingham and Crewe.
I could certainly see West Coast Partnership ordering a mixed fleet of 125 mph Aventras, some of which would be bi-modes and some pure electric.
CrossCountry
CrossCountry has a diverse portfolio of routes, which have every characteristic possible.
- Some are lines with a 125 mph operating speed.
- Some are electrified with 25 KVAC overhead wires.
- Some are electrified with 750 VDC third-rail.
- Some are not electrified.
A bi-mode train with these characteristics would fit well.
- 125 mph capability on both electric and diesel power.
- Battery power for short branch lines.
- Modern passenger facilities.
- Five-cars.
- Ability to work in pairs.
They could actually go for a homogeneous fleet, if they felt so inclined.
That would be a substantial fleet of upwards of fifty five-car trains.
The new CrossCountry franchise will be awarded in August 2019 and start in December 2019.
Other Routes
If the 125 bi-mode Aventra with batteries is built, there could be other routes.
Borders Railway
Why would you run a 125 mph bi-mode Aventra on the 90 mph Borders Railway?
- The Borders Railway will be extended to Carlisle, which will mean, that both ends will be electrified for a few miles.
- This will mean that bi-mode trains with batteries could charge their batteries at both ends of the line.
- If traffic increases, extra cars can be added.
- The trains would be able to use the West Coast Main Line to link the Lake District to Edinburgh.
- They could be given a tourism-friendly interior, to go with the large windows common to all Aventras.
The trains would help to develop tourism in the South of Scotland and the North of England.
East West Rail
The East West Rail between Oxford and Cambridge is going to built without electrification.
- But that doesn’t mean that it should be built with an operating speed in the region of 90 mph!
- The legendary InterCity 125s have been running on lines without electrification at 125 mph since the late 1970s, so it isn’t an unknown practice.
So if the line were to be built for high speed across some of the flattest parts of England, why not unleash the 125 mph bi-mode Aventras?
They could serve Ipswich, Norwich and Yarmouth in the East using their onboard generators.
They could serve Bournemouth, Bristol, Reading and Southampton, if the trains had a dual-voltage capability.
They could use electrification at Bedford, Bletchley, Cambridge and Reading to charge the batteries.
Settle-Carlisle Line
Surely, if the 125 mph bi-mode Aventras are suitable for the Borders Railway, then it should be able to work the Settle-Carlisle Line.
- Both ends of the line are electrified, so batteries could be charged.
- The line needs more and better services.
But the main reason, is that there will be a high-class scenic route between Edinburgh and Leeds.
I estimate that a London to Edinburgh service via Leeds, Settle, Carlisle and the Borders Railway would take six and a half hours, using a 125 mph bi-mode Aventra.
Some tourists love that sort of trip.
Waterloo To Exeter
The West of England Line has the following characteristics.
- It runs between Basingstoke and Exeter.
- It is a hundred and twenty miles long.
- It has a 90 mph operating speed.
- The line is not electrified.
- It is connected to the electrified South Western Main Line to Waterloo.
- The route is electrified between Waterloo and Basingstoke.
- Direct trains take three hours twenty-three minutes between Waterloo and Exeter, with fourteen stops between Basingstoke and Exeter.
- The trains used on the route are twenty-five year-old Class 159 trains.
Would a 125 mph bi-mode Aventra improve the passenger service between Waterloo and Exeter?
- The Aventras are built for fast dwell times at stations, so there could be time saving with all those stops.
- The Aventras could use the third-rail electrification between Waterloo and Basingstoke.
- There may be places, where the operating speed can be increased and the faster Aventras would take advantage.
- The trains could have a passenger-friendly interior and features designed for the route.
The real benefits for South Western Railway and their passengers would come, if the trains could do Waterloo to Exeter in three hours.
Routes For A Pure-Electric Version
There are several routes in the UK, where the following apply.
- Some long-distance trains are run by 125 mph trains.
- The route is fully- or substantially-electrified.
- A proportion of the route allows 125 mph running.
- Sections of the route is only double-track.
Routes satisfying the criteria include.
- The West Coast Main Line
- The East Coast Main Line
- The Great Western Main Line
- The Midland Main Line
On these routes, I believe it would be advantageous, if all passenger trains were capable of operating at 125 mph.
This is cause if all trains were running at 125 mph, they could be more closely spaced, thus increasing capacity.
Digital signalling would probably be needed.
There are several train services,, that use the electrified 125 mph sections of these routes.
Birmingham/Liverpool/Manchester To Edinburgh/Glasgow
TransPennine Express, are replacing their current Siemens 110 mph Class 350 trains on this service, with new CAF 125 mph Class 397 trains.
Euston To The West Midlands, Liverpool And Preston
West Midland Trains are replacing some of their current Siemens 110 mph Class 350 trains with new Aventras.
Information is scarce at the moment, but could some of these new Aventras be 125 mph units for working on the West Coast Main Line?
Leeds/York To Edinbugh
TransPennine Express run trains on this route.
St. Panvras To Corby
The Corby Branch is being upgraded.
- Double-track
- 125 mph running
- Electrification
The section of the Midland Main Line between St. Pancras and Glendon Junction is also being upgraded to allow as much 125 mph running as possible.
If 125 mph bi-mode trains are to be used from St. Pancras to Derby, Nottingham and Sheffield, then surely, it would be logical to use a pure-electric version of the train between St. Pancras and Corby?
Various documents and web pages say, that the St. Pancras to Corby services are going to be worked by 110 mph Class 387 trains. Surely, faster 125 mph trains, which had been designed for the route would be better for passengers and the train operating company.
From my experience of scheduling, the section of the Midland Main Line between St. Pancras and Bedford, must be a nightmare to timetable successfully.
- There are two train operating companies using the route, who go a hundred miles in different directions.
- The Class 700 trains used by Thameslink are only 100 mph trains, so probably can’t use the fast lines too often, as if they do, they’ll delay the expresses..
- Regular passengers object to any change in stopping patterns or journey times.
- Passengers liked to get on express services at Bedford, but they now don’t stop.
- Passengers don’t like the Class 700 trains.
- Luton Airport wants more services.
My experience, says that something radical must be done.
Consider.
- Plans are for two tph between St. Pancras and Corby.
- How many passengers would complain if they ended up in the St. Pancras Thameslink platforms, rather than the high-level ones? They’re both equally badly connected to the Underground, buses and taxis.
- There will be four tph between Bedford and London all day on Thameslink, with an extra four tph in the Peak.
- Some or all of these services will call at both Luton and Gatwick Airports.
- Looking at the two semi-fast services. which both run at tw trph, they seem to stop virtually everywhere.
I think it would be possible for the two tph St. Pancras to Corby services to become express services between Corby, Gatwick Airport and Brighton.
- The services would only stop at Kettering, Bedford, Luton, Luton Airport Parkway, St. Albans, West Hampstead Thameslink, St. Pancras Thameslink, Farringdon, City Thameslink, Blackfriars, London Bridge and East Croydon.
- The services would use the 125 mph fast lines North of St. Pancras, as much as possible.
- Corby services would always call at St. Pancras Thameslink.
- The trains would be designed for both Airport services and long-distance commuting.
- The trains would be maximum length.
Obviously, this is my rough idea, but something like it might satisfy the stakeholders, more than what is proposed.
I think there are also other services, which are fully electrified, which could be upgraded, so that they would be suitable for or need 125 mph electric trains.
Kings Cross To King’s Lynn
I wrote about this route in Call For ETCS On King’s Lynn Route.
Portsmouth Direct Line
Under Topography Of The Line in the Wikipedia enter for the Portsmouth Direct Line, this is said.
The central part of the route, from Guildford to Havant, runs through relatively thinly populated country. The line was designed on the “undulating principle”; that is, successive relatively steep gradients were accepted to reduce construction cost. In the days of steam operation this made the route difficult for enginemen.
But with.
- A second man in the cab, in the shape of the train’s computer, juggling the power.
- Regenerative braking to the batteries saving energy for reuse when needed.
- Bags of grunt from the traction motors.
The pure electric version of the 125 mph Aventra might just have the beating of the topography.
South Western Railway plan to introduce an older train from Litchurch Lane in Derby on this route, in the shape of the last of the Mark 3s, the Class 442 train or the Wessex Electrics, which were built in the 1980s.
It will be interesting to see how a 125 mph pure electric Aventra compares to something made in the same works, thirty years earlier.
Waterloo To Southampton, Bournemouth and Weymouth
The South Western Main Line goes to Southampton Central, Bournemouth and Weymouth.
- It is a 100 mph line
- It is fully-electrified.
Would a 125 mph pure-electric Aventra be able to put the hammer down?
I’m sure Network Rail can improve the line to a maximum safe line-speed.
Conclusion
If Bombardier build a 125 mph bi-mode Aventra with batteries, there is a large market. Especially, if there is a sibling, which is pure electric.
Mathematics Of A Bi-Mode Aventra With Batteries
This article in Rail Magazine, is entitled Bombardier Bi-Mode Aventra To Feature Battery Power.
A few points from the article.
- Development has already started.
- Battery power could be used for Last-Mile applications.
- The bi-mode would have a maximum speed of 125 mph under both electric and diesel power.
- The trains will be built at Derby.
- Bombardier’s spokesman said that the ambience will be better, than other bi-modes.
- Export of trains is a possibility.
It’s an interesting specification.
Diesel Or Hydrogen Power?
Could the better ambience be, because the train doesn’t use noisy and polluting diesel power, but clean hydrogen?
It’s a possibility, especially as Bombardier are Canadian, as are Ballard, who produce hydrogen fuel-cells with output between 100-200 kW.
Ballard’s fuel cells power some of London’s hydrogen buses.
The New Routemaster hybrid bus is powered by a 138 kW Cummins ISBe diesel engine and uses a 75 kWh lithium-ion battery, with the bus being driven by an electric motor.
If you sit in the back of one of these buses, you can sometimes hear the engine stop and start.
In the following calculations, I’m going to assume that the bi-mode |Aventra with batteries has a power source, that can provide up to 200 kW, in a fully-controlled manner
Ballard can do this power output with hydrogen and I’m sure that to do it with a diesel engine and alternator is not the most difficult problem in the world.
The Mathematics
Let’s look at the mathematics!
I’ll assume the following.
- The train is five cars, with say four motored cars.
- The empty train weighs close to 180 tonnes.
- There are 430 passengers, with an average weight of 80 Kg each.
- This gives a total train weight of 214.4 tonnes.
- The train is travelling at 200 kph or 125 mph.
- A diesel or hydrogen power pack is available that can provide a controllable 200 kW electricity supply.
These figures mean that the kinetic energy of the train is 91.9 kWh. This was calculated using Omni’s Kinetic Energy Calculator.
My preferred battery arrangement would be to put a battery in each motored car of the train, to reduce electrical loses and distribute the weight. Let’s assume four of the five cars have a New Routemaster-sized battery of 55 kWh.
So the total onboard storage of the train could easily be around 200 kWh, which should be more than enough to accommodate the energy generated , when braking from full speed..
I wonder if the operation of a bi-mode with batteries would be something like this.
- The batteries would power everything on the train, including traction, the driver’s systems and the passenger facilities, just as the single battery does on New Routemaster and other hybrid buses.
- The optimum energy level in the batteries would be calculated by the train’s computer, according to route, passenger load and the expected amount of energy that would be recovered by regenerative braking.
- The batteries would be charged when required by the power pack.
- A 200 kW power pack would take twenty-seven minutes to put 91.9 kWh in the batteries.
- In the cruise the power pack would run as required to keep the batteries charged to the optimum level and the train at line speed.
- If the train had to slow down, regenerative braking would be used and the electricity would be stored in the batteries.
- When the train stops at a station, the energy created by regenerative braking is stored in the batteries on the train.
- I suspect that the train’s computer will have managed energy, so that when the train stops, the batteries are as full as possible.
- When moving away from a stop, the train would use the stored battery power and any energy used would be topped up by the power pack.
The crucial operation would be stopping at a station.
- I’ll assume the example train is cruising at 125 mph with an energy of 91.9 kWh.
- The train’s batteries have been charged by the onboard generator, on the run from the previous station.
- But the batteries won’t be completely full, as the train’s computer will have deliberately left spare capacity to accept the expected energy from regenerated braking at the next station.
- At an appropriate distance from the station, the train will start to brake.
- The energy of the train will be transferred to the train’s batteries, by the regenerative braking system.
- If the computer has been well-programmed, the train will now be sitting in the station with fully-charged batteries.
- When the train moves off and accelerates to line speed, the train will use power from the batteries.
- As the battery power level drops, the onboard generator will start up and replace the energy used.
This sequence of operations or something like it will be repeated at each station.
One complication, is that regenerative braking is not one hundred percent efficient, so up to thirty percent can be lost in the braking process. In our example 125mph train, this could be 27.6 kWh.
With an onboard source capable of supplying 200 kW, this would mean the generator would have to run for about eight and a half minutes to replenish the lost power. As most legs on the proposed routes of these trains, are longer than that, there shouldn’t be too much of a problem.
If it sounds complicated, it’s my bad explanation.
This promotional video shows how Alstom’s hydrogen-powered Coradia iLint works.
It looks to me, that Bombardier’s proposed 125 mph bi-mode Aventra will work in a similar way, with respect to the batteries and the computer.
But, Bombardier Only Said Diesel!
The Rail Magazine article didn’t mention hydrogen and said that the train would be able to run at 125 mph on both diesel and electric power.
I have done the calculations assuming that there is a fully-controllable 200 kW power source, which could be diesel or hydrogen based.
British Rail’s Class 150 train from 1984, has two 215 kW Cummns diesel engines, so could a five-car bi-mode train, really be powered by a single modern engine of this size?
The mathematics say yes!
A typical engine would probably weigh about 500 Kg and surely because of its size and power output, it would be much easier to insulate passengers and staff from the noise and vibration.
Conclusion
I am rapidly coming to the conclusion, that a 125 mph bi-mode train is a practical proposition.
- It would need a controllable hydrogen or diesel power-pack, that could deliver up to 200 kW
- Only one power-pack would be needed for a five-car train.
- For a five-car train, a battery capacity of 300 kWh would probably be sufficient.
From my past professional experience, I know that a computer model can be built, that would show the best onboard generator and battery sizes, and possibly a better operating strategy, for both individual routes and train operating companies.
Obviously, Bombardier have better data and more sophisticated calculations than I do.
Bombardier Bi-Mode Aventra To Feature Battery Power
The title of this post is the same as this article in Rail Magazine.
A few points from the article.
- Development has already started.
- Battery power could be used for Last-Mile applications.
- The bi-mode would have a maximum speed of 125 mph under both electric and diesel power.
- The trains will be built at Derby.
- Bombardier’s spokesman said that the ambience will be better, than other bi-modes.
- Export of trains is a possibility.
Bombardier’s spokesman also said, that they have offered the train to three new franchises. East Midlands, West Coast Partnership and CrossCountry.
In some ways, I am not surprised about what is said in this article.
Another article on Christian Wolmar’s web site, is entitled Bombardier’s Survival Was The Right Kind Of Politics.
This is said.
Bombardier is not resting on its laurels. Interestingly, the company has been watching the problems over electrification and the fact that more of Hitachi’s new trains will now be bi-mode because the wires have not been put up in time. McKeon has a team looking at whether Bombardier will go into the bi-mode market: ‘The Hitachi bi-mode trains can only go 110 mph when using diesel. Based on Aventra designs, we could build one that went 125 mph. This would help Network Rail as it would not have to electrify everywhere.’ He cites East Midlands, CrossCountry and Wales as potential users of this technology.
The article was published in February 2017 and mentions, 125 mph on diesel and two of the companies in the recent article.
The Design Of The Trains
My thoughts are as follows.
The Starting Point
I’m pretty certain that if you wanmt to create a 125 mph bi-mode train, you start with a 125 mph electric train, if you want a high degree of commonality between the two trains.
Bombardier haven’t yet built any of their Aventras for West Midland Trains, but as they will use the West Coast Main Line extensively, will they be 125 mph trains and not 110 mph trains, as is said in Wikipedia?
Aventras And Battery Power
I will believe until Bombardier say I’m wrong, that Crossrail’s Class 345 trains, which are Aventras, use batteries for the following purposes.
- To handle regenerative braking.
- To limp the train out of the tunnel or to the next station or safe exit point, if there should be a catastrophic power failure.
- To lessen the amount of electricity fed to the trains in the tunnels.
- To allow features like remote wake-up, which need a train to have some form of power at all times.
- To move trains in sidings and depots without having live electrification.
- To run passenger features, when the power fails.
Effectively, the Class 345 trains have electricity as a main power source and batteries for energy storage and a secondary or emergency power source.
I talked to one of their staff, who was training drivers on Crossrail’s Aventras. The conversation went something like this.
- Me: “What happens, when the Russians hack the power supply?”
- Driver-Trainer: “We switch the train to emergency power!”
- Me: “You mean batteries?”
- Driver-Trainer: (Pause, then something like) “Might be!”
Can anybody think of another way to have emergency power on the train?
Electric Traction, Regenerative Braking and Batteries
Bi-mode trains and Alstom’s hydrogen-powered Coradia iLint are electrically powered at all times.
This means that under electric, diesel or hydrogen power, the traction motors can generate electricity to brake the train.
On an electric train, this electricity is returned through the overhead wire or third rail to power other nearby trains. This electricity could also be stored in an onboard battery, just as it is in a hybrid or battery-electric vehicle.
Driving A Bi-Mode Train With Batteries
The bi-mode Aventra could have electricity from one of four power sources.
- 25 KVAC overhead electrification.
- 750 VDC third-rail electrification.
- An onboard electricity generator powered by diesel fuel or hydrogen.
- Batteries
So will the driver need to keep switching power sources?
I am a Control Engineer by training and optimising the best power to use is a typical problem for someone with my training and experience.
The train’s computer would take all the information about the route, timetable, signal settings, battery charge level, train loading, weather and other factors and drive the train automatically, with the driver monitoring everything thoroughly.
Aircraft have been flown in a similar fashion for decades.
I look in detail, at the mathematics of a bi-mode Aventra with batteries in Mathematics Of A Bi-Mode Aventra With Batteries.
I came to the following conclusions.
I am rapidly coming to the conclusion, that a 125 mph bi-mode train is a practical proposition.
- It would need a controllable hydrogen or diesel power-pack, that could deliver up to 200 kW
- Only one power-pack would be needed for a five-car train.
- For a five-car train a battery capacity of 300 kWh would probably be sufficent.
From my past professional experience, I know that a computer model can be built, that would show the best onboard generator and battery sizes, and possibly a better operating strategy, for both individual routes and train operating companies.
Obviously, Bombardier have better data and more sophisticated calculations than I do.
Note, that everything I proposed, is well within the scope of modern engineering, so other companies like CAF and Stadler, who are actively involved in rail application of battery technology, could join the party.
This picture is a visualisation of a Stadler Class 755 train, which they are building for Greater Anglia.
Note the smaller third car, which contains the diesel engine of this hybrid train. Is there room for batteries as well?
I can’t find any information on the web about the power train of the Class 755 train, but this article in the Railway Gazette, describes another Stadler bi-mode Flirt, that Stadler are building for Italy.
This is said.
The units will be rated at 2 600 kW with a maximum speed of 160 km/h when operating from 3 kV DC electrification, and 700 kW with a maximum speed of 140 km/h when powered by the two Stage IIIB compliant Deutz TCD 16.0 V8 diesel engines.
There is provision to add up to two more cars if required to meet an increase in ridership. Two more engines could be added, or the diesel module removed if only electric operation is needed.
Note.
- The Deutz diesel engines are rated at 520 kW.
- As 700 kW is the power of the train, I suspect each engine generator creates 350 kW of power.
- 160 km/h would be ideal for the Great Eastern Main Line
- 140 km/h would be more than adequate for roaming around East Anglia
I suspect that if batteries were used on this train, that the engines would be smaller.
We will see in May 2019, when the trains enter service.
Diesel Or Hydrogen Generator
Electricity generation using a diesel generator and electricity generator from a hydrogen fuel cell, each have their own advantages.
- Diesel fuel has a higher energy density than hydrogen
- Diesel engines create a lot of noise and vibration and emit carbon dioxide, noxious gases and particulates.
- Hydrogen fuel cells can be silent and only emit water and steam.
- Ballard who are a Canadian company and a leading manufacturer of hydrogen fuel-cells, manufacture one for use in rail applications which has an output of 100 kW, that weighs 385 Kg.
- MTU make the diesel engine for a Class 800 train, which has an output of over 600 kW, that weighs 5000 Kg.
- Hydrogen storage is probably heavier and more complicated than diesel storage.
- Both generators can be fitted into convenient rectangular power packs.
I would envisage that in the future, hydrogen electricity generators will get more efficient, lighter in weight and smaller in size for a given power output.
I don’t think it is unreasonable to believe, that within a reasonable number of years, hydrogen generators and their hydrogen storage tank, will be comparable in weight and size to current diesel generators and fuel tanks.
Accelerating A Bi-Mode Train With Batteries
The major use of electricity on a 125 mph train, will be in accelerating the train up to line speed. The energy needed will be.
- Proportional to the mass of the train. This is why your car accelerates better, when it’s just you in the car and you don’t have your overweight mother-in-law in the back.
- Proportional to the square of the velocity.
I have calculated that a five-car bi-mode Aventra, carrying 430 passengers and travelling at 125 mph, will have a kinetic energy of 91.9 kWh.
Obviously, using electricity from electrification is the best way to accelerate a train.
- Electricity from electrification is probably cheaper and more convenient, than that from an onboard electricity generator.
- If diesel is not used to power the train, there is no noise and vibration from an onboard diesel generator.
- A route with a lot of running on onboard fuel, means more fuel has to be carried.
Using electricity stored in batteries on the train, is also a good way to accelerate a train, but the batteries must have enough charge.
The onboard electricity generator will be used, when there is no electrification and the power stored in the batteries is approaching a low level.
|When Bombardier’s spokesman says, that the ambience will be good, control of the train’s power sources has a lot to do with it.
Could he have been hinting at hydrogen, as hydrogen fuel cells do not have high noise and vibration levels?
Cruising A Bi-Mode Train With Batteries
Newton’s First Law states.
Every body continues in its state of rest or uniform motion in a straight line, unless impressed forces act on it.
If you have a train on a railway track moving at a constant speed, the following forces are acting to slow the train.
- Aerodynamic forces, particularly on the front of the train.
- Rolling friction of the steel wheel on a steel rail.
- Bends and gradients in the track.
- Speed limits and signals.
So the driver and his control system will have to feed in power to maintain the vrequired spreed.
I have sat on the platform at Stratford, whilst an Aventra has gone past at speed. I wrote about it in Class 345 Trains Really Are Quiet!
This was my conclusion.
Bombardier have applied world class aviation aerodynamics to these trains. Particularly in the areas of body shape, door design, car-to-car interfaces, bogies and pantographs.
Remember too, that low noise means less wasted energy and greater energy efficiency.
In addition steel wheel on steel rails is a very efficient way of moving heavy weights. Bombardier have a reputation for good running gear.
Once a train has reached its cruising speed, appropriate amounts of power will be fed to the train to maintain speed.
But compared to the power needed to accelerate the train, they could be quite small.
For small amounts of power away from electrification, the control system will use battery power if it is available and can be used.
The onboard electricity generator would only be switched in, when larger amounts of power are needed or the battery power is low.
Slowing A Bi-Mode Train With Batteries
The regenerative braking will always be used, with the energy being stored in the batteries, if there is free capacity.
Imagine the following.
- A bi-mode making a stop at Leicester station on the Midland Main Line.
- It is doing 100 mph before the stop on the main line.
- It will be doing 100 mph after the stop on the main line.
The energy of the train after Leicester will be roughly the same as before, unless the mass of the train has changed, by perhaps a large number of passengers leaving or joining the train.
Let’s assume that the energy at 100 mph in the train is X kWh
- When the train brakes for Leicester this energy will be transferred to the train’s batteries, if there is capacity.
- On accelerating the train, it will need to acquire X kWh. It couldn’t get all of this from the batteries, as for various reasons the overall efficiency of this sort of system is about seventy to ninety percent.
- The onboard electricity generator will have to supply a proportion of the energy to get the train back up to 100 mph.
But in a diesel train it will have to supply all the energy to get back to 100 mph.
Where Would I Put The Batteries?
Aventras seem to have a lot of powered-bogies, so to keep cable runs short to minimise losses and maximise the efficiency of the regenerative braking, I would put a battery in each car of the train.
This would also distribute the weight evenly.
Where Would I Put The Electricity Generators?
Diesel engines always seem to be noisy, when they are installed under the floor of a train. I’ve travelled a lot in Bombardier’s Turbostars and although they are better than the previous generation, they are still not perfect.
I’ve also travelled in the cab of a Class 43 locomotive, with a 2,250 hp diesel engine close behind me. It was very well insulated and not very noisy.
As I said earlier, the most intensive use of the onboard generators will come in accelerating a train to operating speed, where no electrification or battery power is available. There is only so much you can do with insulation!
Stadler, who are building the Class 755 train for Greater Anglia, have opted to put a short diesel generator car in the middle of the train.
This was an earlier train, where Stadler used the technique.
There are reports in Wikipedia, that the ride wasn’t good, but I’m sure Stadler has cracked it for their new 100 mph bi-mode trains.
Creating a bi-mode by adding an extra motor car into the middle of an electric train could be a serious way to go.
- The dynamics are probably better understood now
- A powerful diesel engine could be fitted.
- Batteries could be added.
- Insulating passengers and staff from the noise and vibration would surely be easier.
- There could be a passage through the car, to allow passengers and staff to circulate.
In an ideal world, a four-car electric train could be changed into a five-car bi-mode train, by adding the motor car and updating the train software.
In Mathematics Of A Bi-Mode Aventra With Batteries, I came to the conclusion, that if the batteries are used in conjunction with the power-pack, that a single power-pack of about 200 kW could be sufficient to power the train. This would be smaller and lighter in weight, which would probably mean it could be tucked away under the floor and well-insulated to keep noise and vibration from passengers and staff.
In this article in Global Rail News from 2011, which is entitled Bombardier’s AVENTRA – A new era in train performance, gives some details of the Aventra’s electrical systems. This is said.
AVENTRA can run on both 25kV AC and 750V DC power – the high-efficiency transformers being another area where a heavier component was chosen because, in the long term, it’s cheaper to run. Pairs of cars will run off a common power bus with a converter on one car powering both. The other car can be fitted with power storage devices such as super-capacitors or Lithium-ion batteries if required.
This was published six years ago, so I suspect Bombardier have refined the concept.
So could it be that Bombardier have designed a secondary power car, that can be fitted with a battery and a diesel engine of appropriate size?
- Using a diesel engine with batteries means that a smaller engine can be used.
- The diesel engine could also be replaced with a 200 kW hydrogen fuel cell.
I won’t speculate, but Bombardier have a very serious idea. And it’s all down to the mathematics.
What Would Be The Length Of A 125 Mph Bi-Mode Aventra?
Long distance Aventras, like those for Greater Anglia and West Midlands Trains, seem to be five and ten car trains.
This would fit well with the offerngs from other companies, so I suspect five- and ten-cars will be the standard lengths.
Could There Be A Bi-Mode Aventra for Commuter Routes?
The London Overground has ordered a fleet of four-car Class 710 trains.
The Gospel Oak to Barking Line is being extended to a new Barking Riverside station.
In an article in the October 2017 Edition of Modern Railways, which is entitled Celling England By The Pound, Ian Walmsley says this in relation to trains running on the Uckfield Branch, which probably has a terrain not much different to the lines to London.
A modern EMU needs between 3 and 5 kWh per vehicle mile for this sort of service.
The new extension is about a mile, so this would need 20 kWh each way.
This could easily be done with a battery, but supposing a small diesel engine was also fitted under the floor. Would anybody notice the same 138 kW Cummins ISBe diesel engine that is used in a New Routemaster hybrid bus?
I doubt it.
It is a revealing to calculate the kinetic energy of a fully-loaded Class 710 train. I estimate that it under 50 kWh, if it was travelling at 90 mph, which would rarely be achieved on the Gospel Oak to Barking Line.
Could Bombardier Be Serious About Exporting Bi-Mode Aventras?
In my opinion, the Aventra is a good train an it seems to sell well in its electric form to train operating companies in the UK.
But would it sell well in overseas markets like the United States and Canada, India and Australia?
They obviously know better than I do, so we should take their statements at face value.
The Prospective Customers
The Rail Magazine article mentions three prospective customers.
I deal with them and other possiblilities in Routes For Bombardier’s 125 Mph Bi-Mode Aventra.
This was my conclusion.
If Bombardier build a 125 mph bi-mode Aventra with batteries, there is a large market.
It looks like the company has done a lot of research.
Conclusion
Bombardier are designing a serious train.
What Is The Operating Speed Of Class 710 Trains?
So far, five classes of Aventra trains have been allocated TOPS numbers and their own Wikipedia pages.
- Crossrail – Class 345 trains – 145 kph
- London Overground – Class 710 trains – Speed not disclosed
- Greater Anglia – Class 720 trains – 160 kph
- South Western Railway – Class 701 trains – 160 kph
- c2c – Class 711 trains – 160 kph
The other orders for West Midlands Trains are given as 145 kph for the Cross-City Line and 180 kph for longer distance trains, in Wikipedia.
Looking at these speeds, I think that the operating speed of the Class 710 trains, must either be the 145 kph of the Crossrail trains or the 160 kph of the suburban trains. Or they could be the 121 kph of London Overground’s Class 378 trains.
But it has not been disclosed.
As probably most Aventras use similar running gear and electrical and control systems, I wouldn’t be surprised that maximum operating speed, is just a setting in the train’s control computer.
London Overground’s Aventra Routes
Timings on London Overground’s routes, that will be run by Class 710 trains are as follows.
- Euston – Watford Junction – 47 minutes – 15 stops
- Liverpool Street – Cheshunt – 39 minutes – 15 stops
- Liverpool Street – Chingford – 27 minutes – 6 stops
- Liverpool Street – Enfield Town – 33 minutes – 13 stops
Comparing the new Class 710 trains to the current Class 315 and Class 317 and Class 378 trains, there are or may be performance differences.
- Class 315 and Class 378 are slower trains with a 121 kph operating speed.
- Class 317 trains have an operating speed of 161 kph.
- Dwell times mat be less on the new trains compared to some or all of the existing types.
So how will these differences effect the various routes?
Euston – Watford Junction
There seems to be long turnrounds on this service and I’m fairly certain faster trains could run this service more efficiently, which may mean that the same number of trains could run at a frequency of four trains per hour (tph).
Liverpool Street – Cheshunt
This service is based on a six minute turnround and I suspect could be run more efficiently, if a faster train could get each way in under thirty minutes.
Liverpool Street – Chingford
It looks like this four tph service is run pretty efficiently, but there is a ten minute turnround at Chingford.
Liverpool Street – Enfield Town
The Liverpool Street to Enfield Town service waits nineteen minutes before returning, so small savings in dwell times and a faster train, might allow a two tph service to be setup, where trains depart on the half-hour, using just two trains.
Four tph, which is planned to start on this route in 2019, would need just four trains.
Summery Of London Overground Routes
Faster trains with shorter dwell times will certainly improve the timings and frequency of London Overground’s services, that they intend to run with Class 710 trains.
I’m pretty certain, that they will enable the following.
- Four tph – Euston to Watford Junction
- Four tph – Liverpool Street to Enfield Town
They will also improve timings on Liverpool Street to Cheshunt.
Conclusion
But what will be the operating speed of the Class 710 trains?
I said it will be somewhere between 145 kph (90 mph) and 160 kph (100 mph)
Or it could be the 12kph of the current Class 378 trains.
Consider.
- I think that 145 kph, will be able to handle the two planned increased frequencies of four tph.
- 145 kph is identical to the Crossrail trains.
- 160 kph is identical to the Greater Anglia trains.
- 121 kph is identical to the London Overground Class 378 trains.
- 160 kph seems to be the speed of suburban Aventras.
It’s a difficult one to call!
Is Crossrail Having An Affect On Train Purchases In The South East?
Crossrail and Crossrail 2 are designed to take-over suburban lines out of London.
Crossrail’s Trains
Crossrail has chosen to use Class 345 trains, which are Aventras built by Bombardier in Derby.
I would suspect that if Crossrail 2 is built, it will use the same trains, as a unified fleet must be easier and more affordable to manage.
Crossrail’s Suburban Routes
It is worth looking at the routes these services will take over and their future train fleets.
Great Eastern Main Line To Shenfield
The slow lines of the Great Eastern Main Line have been taken over by Crossrail to provide a service to their terminus at Shenfield.
Greater Anglia have chosen to replace their assorted suburban fleet with Class 720 trains, which are also Aventras.
This must be a sensible move, as there is likely to be a certain amount of platform sharing between Crossrail and Greater Anglia between Liverpool Street and Shenfield.
Wheelchair ramps would be the same, or would level access from platform to train be provided.
These pictures show Class 345 trains at Liverpool Street and Stratford stations.
The step is not bad, but it is less than some on the London Overground. However, a few well-placed Harrington Humps would probably make entry and exit a lot easier.
It also must help, if Crossrail extends its route past Shenfield to perhaps Beaulieu, Chelmsford or Southend Victoria. Platforms updated for Greater Anglia’s Class 720 trains, would surely fit Crossrail’s Class 345 trains.
I also don’t think there are any platform length issues, although my research says that ten-car Class 720 trains are longer than nine-car Class 345 trains.
Great Western Main Line To Heathrow and Reading
The slow lines of the Great Western Main Line have been taken over by Crossrail to provide a service to their termini at Heathrow and Reading.
Great Western Railway (GWR) were forced to use Class 387 trains, due to electrification delays on the Great Western Main Line and late deliveries of Class 700 trains for Thameslink.
This is all a bit of a dog’s breakfast and I think there’ll be a bit of a sort-out, with perhaps..
- Electrification to Basingstoke, Newbury and Oxford.
- Crossrail with an increased frequency, serving all stations between London and Reading.
- Bedwyn and Oxford would be served by GWR’s five-car Class 800 trains, which would be at 125 mph between Eddington and Reading.
There could be some rather nice Class 387 trains going cheap?
But the result would be the slow lines would be Crossrail-only!
West Coast Main Line To Milton Keynes
This is a possible extension to Crossrail, from the mega hub at Old Oak Common station.
The current local operators on the West Coast Main Line are London Overground and West Midlands Trains.
Both operators have ordered new Aventras for these routes out of London.
London Overground is even replacing modern Class 378 trains with new Class 710 trains on the Watford DC Line.
Suburban Services Out Of Waterloo
If Crossrail 2 gets built, then some of these services will be taken over.
South Western Railway (SWR) have already ordered Class 701 trains for these routes.
This would appear to be a sensible move, as any improvements to platforms and stations made by SWR, will be compatible with Crossrail 2.
West Anglia Main Line To Broxbourne
If Crossrail 2 gets built, then some of these services along the West Anglia Main Line, will be taken over.
Greater Anglia have already ordered Class 720 trains for these routes.
This would appear to be another sensible move, as any improvements made by Greater Anglia, will be compatible with Crossrail 2.
Even after Crossrail 2 opens, Greater Anglia services will still be using the West Anglia Main Line, so there should be no compatibility problems.
North Kent Line To Abbey Wood, Ebbsfleet and Gravesend
The Mayor of London, several London Boroughs and other groups are pushing to extend Crossrail to Ebbsfleet.
Currently, there is a mixture of trains on the North Kent Line,
Consider.
- .In a few years time, there will be a new franchise holder.
- It is likely that a lot of trains will be replaced.
- It is likely that Crossrail and existing North Kent services will share a two-track railway.
It strikes me that there is a high chance that these replacement trains will be Aventras, as this will create a more efficient railway.
How Compatible Are Class 700 Trains With Aventras?
This question has to be asked, as the two different classes of trains will share routes and platforms.
- Along the North Kent Line if Crossrail is extended.
- Around the Cambridge area, where Thameslink and Greater Anglia share platforms.
I would assume that they must be very compatible, as the railway press isn’t saying anything to the contrary.
Surely, in a sensible world, both Thameslink and Crossrail would have used the same class of train!
Conclusion
It looks like there are advantages to having a line run by one family of trains.
- All trains will fit all platforms.
- Platform procedures will be similar for passengers and staff.
- Aventras can be fitted with the latest signalling and control systems.
Will these shared characteristics result in extra capacity?
Stadler Publish More Details On Greater Anglia’s Flirts
These pictures are on several web sites and show more details on how Stadler is creating Greater Anglia’s Class 745 trains.
If you compare the first and third pictures, it would appear that the cab is a separate construction, probably made out of a variety of materials like steel, aluminium and glass reinforced plastic.
The body could be similar to that of a Bombardier Electrostar or Aventra and made of three aluminium sections welded together.
The cross-section seems simpler than that of an Aventra, which as this picture shows is double-skinned with ribs.
Are the sides and roof of Stadler Flirts extruded or fabricated?
But then Bombardier designed the Aventra bodies to be made in large numbers, close to the production line, whereas Stadler build the bodies in Hungary.
Thoughts On A Hydrogen-Powered Bi-Mode High Speed Train
My stockbroker and pension fund manager keeps contacting me about hydrogen power. There seems to be a lot of money chasing few good investments.
What I find surprising is that two of the leading fuel cell companies are Canadian; Ballard and Hydrogenics, with one supplying Alstom with fuel cells for their hydrogen powered train.
Bombardier at Derby, who are another Canadian company, have been very quiet on hydrogen.
These are my thoughts.
The Aventra Is A Plug-And-Play Train
I believe that the control system on an Aventra looks at the train and determines what cars make up the train. Hitachi certainly do this with their A-trains like Class 800 trains and I suspect that the control systems of most modern trains can do it, as it allows trains to be lengthened and shortened as required.
Electric Multiple Units Have An Electrical Power Bus
I believe that most electric multiple units have an electrical power bus that connects all cars to the electrical supply from the pantograph or third rail shoes.
On a Btoitish Rail-era Class 319 train, which has DC traction motors, this is 750 VDC, but on modern trains, which generally have AC traction motors, it is probably something more appropriate.
The Design Trend In Electrical Multiple Units Is To Have More Powered Axles
Bombardier are certainly going this route with the new Class 345 trains for Crossrail.
I found this snippet on the Internet which gives the formation of the new Class 345 trains.
When operating as nine-car trains, the Class 345 trains will have two Driving Motor Standard Opens (DMSO), two Pantograph Motor Standard Opens (PMSO), four Motor Standard Opens (MSO) and one Trailer Standard Open (TSO). They will be formed as DMSO+PMSO+MSO+MSO+TSO+MSO+MSO+PMSO+DMSO.
So as both PMSO cars are there, I would assume that the current seven-car trains are two MSO cars or an MSO and a TSO car short of a full-train.
The power cars/total cars ratio will be as follow.
- Seven-car train – 0.86
- Nine-car train – 0.89
In The Formation Of A Class 707 Train, I showed that the ratio for Class 707 trains is just 0.40, whereas Greater Anglia’s siomilar five-car Class 720 train appears to have five cars with motors.
Could this increase in the number of powered axles mean the following?
- Better acceleration for the same electrical power.
- More, but smaller and lighter traction motors.
- Less wheel-slip in some rail conditions.
- Each axle could be controlled individually, to minimise wheel-slip, which leads to extra maintenance costs.
- Smoother regenerative braking, as effectively every axle is braked without the use of inefficient friction brakes.
- If batteries are used for regenerative braking, then one smaller battery can be fitted to each car with motors.
But the extra traction motors could cost more.
Only Bombardier seem to have gone all the way. Perhaps, they have found that modern manufacturing methods can produce more affordable traction motors.
One consequence of distributed power, is that each car will have a high electrical load, so there will be a need for a sophisticated electrical power bus going to every can on the train.
A Car With A Diesel-Powered Electricity Generator
I have ridden in the cab of a Class 43 locomotive. Admittedly, it was one that had been modified with a new diesel engine, I was surprised how quiet 2,250 hp can be, just a few feet away.
Obviously, the sound-proofing was of the highest quality.
This picture shows a Stadler train, which has a diesel-powered car in the middle of the train.
Greater Anglia’s new Class 755 trains will use this technique.
Intriguingly, British Rail designed the record-braking Class 442 train, with all the electrical equipment and traction motors in the middle car of a five-car set.
I suspect because of the design of an Aventra, Bombardier could put a diesel engine in one the middle cars to create a bi-mode Aventra.
Bombardier have said in this article on Christian Wolmar’s web site, that they are working on a 125 mph bi-mode Aventra.
In the Class 172 train, each car has a 360 kW diesel engine, so a five car 125 mph bi-mode train could need a substantial amount of power.
A Car With A Hydrogen-Powered Electricity Generator
In Alstom’s Coradia iLint, the hydrogen tanks and generators are mounted on the roof, thus taking advantage of the larger Continental loading gauge. Wikipedia says this about the train.
The Coradia iLint is a version of the Coradia Lint 54 powered by a hydrogen fuel cell. Announced at InnoTrans 2016, the new model will be the world’s first production hydrogen-powered trainset. The Coradia iLint will be able to reach 140 kilometres per hour (87 mph) and travel 600–800 kilometres (370–500 mi) on a full tank of hydrogen. The first Coradia iLint is expected to enter service in December 2017 on the Buxtehude-Bremervörde-Bremerhaven-Cuxhaven line in Lower Saxony, Germany.
In the UK, there isn’t the space, but I believe that a car could be built with a hydrogen tank and the appropriate size of hydrogen-powered electricity generator.
Bear in mind, that a hydrogen power system will be is a lot quieter and vibrate less, that a diesel one.
The Plug-and-Play nature of an Aventra or other modern trains, would mean that after the train software has been modified, it could detect that the train has a car with a hydrogen-powered electricity generator.
The car would deliver its electricity, when it is require, through the electrical bus.
The train’s computer system would control the generator, so that the level of power needed to move the train was available.
Batteries
Batteries are an integral part of Alstom’s Coradia iLint as this promotional video shows.
I believe that Bombardier make extensive use of batteries in the Aventra for regenerative braking, running for short distances without electrification and electrification failure.
Why Do I Think A Hydrogen-Powered High Speed Train Is Possible?
By High Speed Train, I mean one that can travel at 200 kph or 125 mph.
Most energy is needed to accelerate the train, not to maintain the high cruising speed.
So if you take a train running along a line with only a few stops, that is fairly level with no long climbs, there will be a minimal power requirement, except where accelerating from a stop.
Energy requirement can be reduced by the following.
- Design the line as straight as possible.
- Remove as many gradients as possible.
- Have separate tracks for stopping and high-speed traffic.
- Install a modern signalling system, so that trains run efficiently.
- Remove flat junctions and level crossings
- Have a very efficient train with low rolling resistance and good aerodynamics.
- Have as few stops as possible.
Network Rail seem to be improving the tracks all over the UK to this standard and Point 6 is satisfied by modern trains like Aventras.
Point 7 depends on getting the timetable right.
Adding all these factors together and you can see why I believe a hydrogen-powered High Speed Train is a possibility.
Development
The great advantage of developing a hydrogen-powered train, is that a lot of the initial testing can be done in a lab, as all you need to develop is a power module, that can fit in the train, that can generate the required number of kilowatts.
Independently, the train company would need to develop an electric train capable of 125 mph running.
Deployment
Hydrogen-powered High Speed Trains could run on several lines in the UK.
Midland Main Line
The Midland Main Line is the obvious line for a hydrogen-powered High Speed Train.
- A lot of the route is already capable of 125 mph running.
- Large sections are three or four tracks.,
- The Southern section from Bedford to St. Pancras is electrified, so hydrogen power would only be needed North of Bedford.
- The new East Midlands Franchise will streamline the intermediate stops.
- Parts of the line go through the World Heritage Site of the Derwent Valley and would be difficult to electrify. Quiet hydrogen-powered trains would be acceptable to all.
- Selective electrification could be applied at Derby, Leicester, Nottingham and Sheffield, to charge batteries and accelerate trains.
There is a lot of work going on =North of Bedford as far as Kettering and Corby.
- The Corby branch is being made double track.
- Bedford to Glendon Junction, where trains to Corby leave the Midland Main Line, will become four tracks.
- Tracks will be electrified to Kettering and Corby.
- 125 mph running will be possible as far as Glendon Junction and Corby.
Will the two fast lines be electrified between Kettering and Glendon Junction?
This would enable trains going North from Kettering to accelerate to 125 mph using the electrification, rather than hydrogen or battery power.
The electrification would catapult them the nearly thirty miles to Leicester at 125 mph, with speed maintained by using small amounts of hydrogen or battery power.
Coming South, the train would get to 125 mph leaving Leicester, either using a short length of electrification through the station or by use of the onboard power.
Small amounts of hydrogen or battery power would keep the train at 125 mph, until it could connect to the electrification at Glendon Junction.
I’m assuming that the signalling can keep the fast lines free of slow traffic. But even if they are slowed by a crossing train, regenerative braking using the battery will enable speed to be recovered quickly.
This article on Rail Technology Magazine is entitled DfT Deal Means East Midlands HS2 Station Could Open Early.
East Midlands Hub station would obviously be electrified for HS2 services from Birmingham and London.
So perhaps a few miles of electrification could be added to the Midland Main Line to get trains to operating speed, after a stop at the station.
In addition, could selective electrification be applied at other stations like Derby, East Midlands Parkway, Leicester, Nottingham and Sheffield.
It could be a bit like a game of 125 mph Pass-the-Parcel.
Trains could be at 125 mph for most of the way from St. Pancras to Sheffield, giving a journey time somewhere in the region of ninety minutes.
North Wales Coast Line
I’ve never travelled on the North Wales Coast Line.
- It is around ninety miles long.
- It has an operating speed of 90 mph
- As it’s a coastal line, I suspect that the route is fairly level.
- No-one would complain about the noise reduction of a hydrogen-powered train.
- Virgin’s Class 221 trains take about a hundred minutes from Holyhead to Chester with six stops.
It is a route, where a bi-mode train could probably save some minutes, as they could use the electrification South of Crewe.
Alstom have already set up a base in Widnes and are interested in demonstrating hydrogen trains between Chester and Liverpool via the Halton Curve when it reopens.
But a train with a slightly better performance to the Coradia iLint could be ideal for Liverpool to Chester and along the North Wales Coast.
Basingstoke To Exeter
The West Of England Line goes from Waterloo to Exeter and has the following characteristics.
- The Waterloo to Basingstoke section is forty-eight miles long and electrified.
- The Basingstoke to Exeter section is 124 miles long and not-electrified.
- The route is fairly level.
- The operating speed is 90 mph.
- The route is served by 90 mph Class 159 trains.
This is one of those lines, where a bi-mode train would be ideal.
The route might be suitable for a hydrogen-powered train.
Ashford To Southampton
Between Ashford and Southampton, there is only one section that is not electrified and that is the Marshlink Line, which is just 26 miles long.
Other Routes
I suspect there are other routes, but I do think gentle lines without too many gradients are probably the best lines for hydrogen-powered trains.
Other Trains
As Hitachi’s IEP and Stadler Flirts have similar electrical layouts and design, a similar technique involving hydrogen poower could probably be used.
The Anonymous Widower 