Regenerative Braking On A Dual-Voltage Train
Yesterday, I found this document on the Railway People website, which is entitled Regenerative Braking On The Third Rail DC Network.
Although, the document dates from 2008, it is very informative.
Regenerative Braking On 25 KVAC Trains
The document says this.
For AC stock, incoming power from the National Grid at high voltage is stepped down by a transformer. The AC power is transmitted via OHL to the trains. When the train uses regenerative braking, the motor is used as a generator, so braking the axle and producing electrical energy. The generated power is then smoothed and conditioned by the train control system, stepped up by a transformer and returned to the outside world. Just about 100% of regenerated power is put back into the UK power system.
But I have read somewhere, that you need a 25 KVAC overhead electrification system with more expensive transformers to handle the returned electricity.
Regenerative Braking On 750 VDC Trains
The document says this.
After being imported from the National Grid, the power is stepped down and then AC power is rectified to DC before being transmitted via the 3rd rail. Regenerated Power can not be inverted, so a local load is required. The power has to be used within the railway network. It cannot be exported.
So the electricity, is usually turned into heat, if there is no train nearby.
The Solution That Was Applied
The document then explains what happened.
So, until such time as ATOC started to lobby for a change, regenerative DC braking was going nowhere. But when they did start, they soon got the backing of the DfT and Network Rail. It takes a real combined effort of all organisations to challenge the limiting assumptions.
In parallel, there were rolling stock developments. The point at which all the issues started to drop away was when the Infrastructure Engineers and Bombardier, helped out by some translating consultants (Booz & Company), started to understand that new trains are really quite clever beasts. These trains do understand what voltage the 3rd rail is at, and are able, without the need to use any complicated switch gear – just using software, to decide when to regenerate into the 3rd rail or alternatively, use the rheostatic resistors that are on the train.
Effectively, the trains can sense from the voltage if the extensive third-rail network can accept any more electricity and the train behaves accordingly.
As most of the electric units with regenerative braking at the time were Bombardier Electrostars, it probably wasn’t the most difficult of tasks to update most of the trains.
Some of the Class 455 trains have recently been updated. So these are now probably compatible with the power network. Do the new traction motors and associated systems use regenerative braking?
This document on the Vossloh-Kiepe web site is entitled Vossloh Kiepe enters Production Phase for SWTs Class 455 EMU Re-Tractioning at Eastleigh Depot and describes the updating of the trains. This is said.
The new IGBT Traction System provides a regenerative braking facility that uses the traction motors as generators when the train is braking. The electrical energy generated is fed back into the 750 V third rail DC supply and offsets the electrical demands of other trains on the same network. Tests have shown that the energy consumption can be reduced by between 10 per cent and 30 per cent, depending on conditions. With the increasing cost of energy, regenerative braking will have a massive positive cost impact on the long-term viability of these trains. If the supply is non-receptive to the regenerated power, the generated power is dissipated by the rheostatic brake.
So thirty-five year old British Rail trains now have a modern energy-saving traction system.
Has The Solution Worked On The Third-Rail Network?
The Railway People document goes on to outline how they solved various issues and judging by how little there is about regenerative braking on the third-rail network, I think we can assume it works well.
One Train, Two Systems
If you have a train that has to work on both the 25 KVAC and 750 VDC networks, as Thameslink and Southeastern Highspeed trains do, the trains must be able to handle regenerative braking on both networks.
So is there a better way, than having a separate system for each voltage?
In Do Class 800/801/802 Trains Use Batteries For Regenerative Braking?, I investigated how Hitachi’s new Class 800 trains handle regenerative braking.
A document on Hitachi’s web site provides this schematic of the traction system.
Note BC which is described as battery charger.
The regenerative braking energy from the traction motors could be distributed as follows.
- To provide power for the train’s services through the auxiliary power supply.
- To charge a battery.
- It could be returned to the overhead wires.
Hitachi’s system illustrates how using a battery to handle regenerative braking could be a very efficient way of running a train.
Hitachi’s diagram also includes a generator unit or diesel power-pack, so it could obviously fit a 750 VDC supply in addition to the 25 KVAC system on the Class 800 train.
So we have now have one train, with three power sources all handled by one system.
What Has Happened Since?
As the Hitachi document dates from 2014, I suspect Hitachi have moved on.
Siemens have produced the Class 700 train for Thameslink, which is described in this Siemens data sheet.
Regenerative braking is only mentioned in this sentence.
These new trains raise energy efficiency to new levels. But energy efficiency does not stop at regenerative braking.
This is just a bland marketing statement.
Bombardier are building the first batches of their new Aventra train, with some Class 345 trains in service and Class 710 trains about to enter testing.
Nothing has been said about how the trains handle regenerative braking.
But given that Bombardier have been experimenting with battery power for some time, I wouldn’t be surprised to see batteries involved.
They call their battery technology Primove and it has its own web site.
There is also this data sheet on the Bombardier web site.
Class 387 Trains
There is another train built by Bombardier, that is worth investigating.
The Class 387 train was the last and probably most advanced Electrostar.
- The trains have been built as dual-voltage trains.
- The trains have regenerative braking that works on both electrification types.
- They were built at around the time Bombardier were creating the Class 379 BEMU demonstrator.
- The trains use a sophisticated propulsion converter system called MITRAC, which is also used in their battery trams.
On my visit to Abbey Wood station, that I wrote about in Abbey Wood Station Opens, I got talking to a Gatwick Express driver about trains, planes and stations, as one does.
From what he said, I got the impression that the Class 387/2 trains, as used on Gatwick Express, have batteries and use them to keep the train and passengers comfortable, in case of an electrification failure.
So do these trains use a battery to handle the regenerative braking?
How Big Would Batteries Need To Be On A Train For Regenerative Braking?
I asked this question in a post with the same name in November 2016 and came to this conclusion.
I have a feeling that using batteries to handle regenerative braking on a train could be a very affordable proposition.
As time goes on, with the development of energy storage technology, the concept can only get more affordable.
Bombardier make a Primove battery with a capacity of 50 kWh, which is 180 mega-Joules.
So the braking energy of what mass of train could be stored in one of these batteries?
I got these figures.
- 100 mph – 180.14 tonnes.
- 110 mph – 148.88 tonnes.
What is the mass of a Class 387 train?
This is not available on the Internet but the mass of each car of a similar Class 378 train averages out at 32 tonnes.
Consider these points.
- A Class 387/2 train, has 219 seats, so if we assume each passenger and baggage weighs eighty kilograms, that adds up to 17.5 tonnes.
- As the Class 387 trains have a maximum speed of 100 mph on third-rail electrification, it would appear that a Primove 50 kWh battery could handle the braking energy.
- A Primove 50 battery with its controller weighs 827 Kg. according to the data sheet.
It all looks like using one of Bombardier’s Primove 50 batteries on a Class 387 train to handle the regenerative braking should be possible.
But would Bombardier’s MITRAC be able to use that battery power to drive the train in the most efficient manner? I suspect so!
If the traction layout is as I have outlined, it is not very different to the one published by Hitachi in 2014 on their web site for the Class 800 train.
Conclusion
Hitachi have got their traction layout right, as it can handle any number of power sources.
The Intelligent Multi-Mode Train And Affordable Electrification
Some would say we are at a crisis point in electrification, but I would prefer to call it a crossroads, where new techniques and clever automation will bring the benefits of electric traction to many more rail lines in the UK.
Lines That Need Electric Passenger Services
I could have said lines that need to be electrified, but that is probably a different question, as some lines like the Felixstowe Branch Line need to be electrified for freight purposes, but electric passenger services can be provided without full electrification.
Lines include.
- Ashford to Hastings.
- Borderlands Line.
- Caldervale Line from Preston to Leeds
- Camp Hill Line across Birmingham.
- Huddersfield Line from Manchester to Leeds via Huddersfield.
- Midland Main Line from Kettering to Derby, Nottingham and Sheffield.
- Uckfield Branch Line
There are many others, too numerous to mention.
What Is A Multi-Mode Train?
If a bi-mode train is both electric and diesel-powered, a multi-mode train will have at least three ways of moving.
The Intelligent Multi-Mode Train
The intelligent multi-mode train in its simplest form would be an electric train with these characteristics.
- Electric drive with regenerative braking.
- Diesel or hydrogen power-pack.
- Onboard energy storage to handle the energy generated by braking.
- 25 KVAC and/or 750 VDC operation.
- Automatic pantograph and third-rail shoe deployment.
- Automatic power source selection.
- The train would be designed for low energy use.
- Driver assistance system, so the train was driven safely, economically and to the timetable.
Note the amount of automation to ease the workload for the driver and run the train efficiently.
Onboard Energy Storage
I am sure that both the current Hitachi and Bombardier trains have been designed around energy storage. Certainly, there are several quotes from Bombardier executives that say so.
The first application will be to handle regenerative braking, so that energy can be stored on the train, rather than returned to the electrification.
Onboard energy storage is also important in modern electric trains for other reasons.
- Features like remote train wake-up can be enabled.
- Moving the train short distances in case of power failure.
- When Bombardier started developing the use of onboard energy storage, they stated that one reason was to reduce electrification in depots for reasons of safety.
Onboard energy storage will improve in several ways.
- The energy density will get higher, meaning lighter and smaller storage.
- The energy storage capacity will get higher, meaning greater range.
- The cost of energy storage will become more affordable.
- Energy storage will last longer before needing replacement.
- CAF use a supercapacitor to get fast response and a lithium-ion battery for good capacity.
We underestimate how energy storage will improve over the next few years at our peril.
Automatic Onboard Storage Management
The use of the energy storage will also be optimised for route, passenger load, performance and battery life by the trains automatic power source selection system.
Diesel Power Pack
A conventional diesel power pack to drive the train on lines without electrification.
As the train is electrically-driven, when running under diesel, regenerative braking can still be used, with the generated energy being stored onboard the train.
Hydrogen Power Pack
I believe that hydrogen could be used to generate the electricity required, as it is in some buses.
Operation Of The Multi-Mode Train
I’ve read somewhere that Greater Anglia intend to run their Class 755 trains using electricity, where electrification is available, even if it only for a short distance. This is enabled, by the ability of the train to be able to raise and lower the pantograph quickly and at line speed.
The train’s automatic power source selection will choose the most appropriate power source, from perhaps electrification, stored energy and diesel, based on route, load and the timetable.
Do Any Multi-Mode Trains Exist?
The nearest is probably the Class 800 train, which I believe uses onboard energy storage to handle regenerative braking, as I outlined in Do Class 800/801/802 Trains Use Batteries For Regenerative Braking?.
This article in RailNews is entitled Greater Anglia unveils the future with Stadler mock-up and says this.
The bi-mode Class 755s will offer three or four passenger vehicles, but will also include a short ‘power pack’ car to generate electricity when the trains are not under the wires. This vehicle will include a central aisle so that the cars on either side are not isolated. Greater Anglia said there are no plans to include batteries as a secondary back-up.
So does that mean that Class 755 trains don’t use onboard energy storage to handle regenerative braking?
At the present time, there is no bi-mode Bombardier Aventra.
But in Is A Bi-Mode Aventra A Silly Idea?, I link to an article on Christian Wolmar’s web site, which says that Bombardier are looking into a 125 mph bi-mode Aventra.
My technical brochure for the new Class 769 train, states that onboard energy storage is a possibility for that rebuild of a Class 319 train.
I don’t think it is a wild claim to say that within the next few years, a train will be launched that can run on electric, diesel and onboard stored power.
The Pause Of Electrification
Obviously, for many reasons, electrification of all railway lines is an ideal.
But there are problems.
- Some object to electrification gantries marching across the countryside and through historic stations.
- Network Rail seem to have a knack of delivering electrification late and over budget.
- The cost of raising bridges and other structures can make electrification very bad value for money.
It is for these and other reasons, that the Government is having second thoughts about the direction of electrification.
Is There A Plan?
I ask this question deliberately, as nothing has been disclosed.
But I suspect that not for the first time, the rolling stock engineers and designers seem to be getting the permanent way and electrification engineers out of trouble.
As far as anybody knows, the plan seems to be to do no more electrification and use bi-mode trains that can run under both electrification and diesel-power to provide new and improved services.
Use Of Bi-Mode Trains
Taking a Liverpool to Newcastle service, this would use the electrification to Manchester, around Leeds and on the East Coast Main Line, with diesel power on the unelectrified sections.
If we take a modern bi-mode train like a Class 800 train, some features of the train will help on this route.
- The pantograph can raise or lower as required at line speed.
- It is probably efficient to use the pantograph for short sections of electrification.
- Whether to use the pantograph is probably or certainly should be controlled automatically.
On this route the bi-mode will also be a great help on the fragile East Coast Main Line electrification.
Improving Bi-Mode Train Efficiency
Bi-mode trains may seem to be a solution.
However, as an electrical engineer, I believe that what we have at the moment is rather primitive compared to how the current crop of trains will develop.
Onboard Energy Storage
I said this earlier.
- I am sure that both the current Hitachi and Bombardier trains have been designed to use energy storage.
- CAF use a supercapacitor to get fast response and a lithium-ion battery for good capacity.
This is an extract from the the Wikipedia entry for supercapacitor.
They typically store 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerate many more charge and discharge cycles than rechargeable batteries.
Supercapacitors are used in applications requiring many rapid charge/discharge cycles rather than long term compact energy storage: within cars, buses, trains, cranes and elevators, where they are used for regenerative braking.
Pairing them with a traditional lithium-ion battery seems to be good engineering.
The most common large lithium-ion batteries in public transport use are those in hybrid buses. In London, there are a thousand New Routemaster buses each with a 75 kWh battery.
In the past, there has have been problems with the batteries on New Routemasters and other hybrid buses, but things have improved and I suspect there is a mountain of knowledge both in the UK and worldwide on how to build a reliable, affordable and safe lithium-ion battery in the 75-100 kWh range.
As on the New Routemaster the battery is squeezed under the stairs, these batteries are not massive and I suspect one or more could easily be fitted underneath the average passenger train.
Look at this picture of a Class 321 train.
The space underneath is typical of many electrical multiple units.
How Far Could A Train Travel On Stored Energy?
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.
A modern EMU needs between 3 and 5 kWh per vehicle mile for this sort of service.
So if we take a battery from a New Routemaster bus, which is rated at 75 kWh, this would propel a five-car electric multiple unit between three and five miles.
Suppose though you put a battery of this size in every car of the train. This may seem expensive, but a typical car in a multiple unit and a double-deck bus carry about the same number of passengers.
A battery in each car would give advantages, especially in a Bombardier Aventra.
- Most cars in an appear to be powered, so each traction motor would be close to a battery, which must reduce electrical transmission losses and ease regenerative braking.
- Each car would have its own power supply, in case the main supply failed.
- The weight of the batteries is spread along the train.
If you take any Aventra, with a 75 kWh battery in each car, using Ian’s figures, they would be able to run between fifteen and twenty-five miles on battery power alone.
Quotes by Bombardier executives of a fifty mile range don’t look so fanciful.
What Onboard Energy Storage Capacity Would Be Needed For Fifty Miles?
This article in Rail Engineer, which is entitled An Exciting New Aventra, quotes Jon Shaw of Bombardier on onboard energy storage.
As part of these discussions, another need was identified. Aventra will be an electric train, but how would it serve stations set off the electrified network? Would a diesel version be needed as well?
So plans were made for an Aventra that could run away from the wires, using batteries or other forms of energy storage. “We call it an independently powered EMU, but it’s effectively an EMU that you could put the pantograph down and it will run on the energy storage to a point say 50 miles away. There it can recharge by putting the pantograph back up briefly in a terminus before it comes back.
What onboard energy storage capacity would be needed for the quoted fifty miles?
I will use these parameters.
- Ian Walmsley said a modern EMU consumes between 3 and 5 kWh for each vehicle mile.
- All vehicles are powered and there is one battery per vehicle.
This will result in the following battery sizes for different EMU consumption rates.
- 3 kWh/vehicle-mile – 150 kWh
- 4 kWh/vehicle-mile – 200 kWh
- 5 kWh/vehicle-mile – 250 kWh
These figures show that to get a smaller size of battery, you need a very energy-efficient train. At least lighting, air-conditioning and other electrical equipment is getting more efficient.
The 379 IPEMU Experiment On The Mayflower Line
In 2015, I rode the battery-powered Class 379 train on the 11.2 mile long Mayflower Line.
I was told by the engineer monitoring the train on a laptop, that they generally went to Harwich using the overhead electrification, charging the battery and then returned on battery power.
Ian Walmsley in his Modern Railways article says that the batteries on that train had a capacity of 500 kWh.
This works out at just over 11 kWh per vehicle per mile.
Considering this was an experiment conducted on a scheduled passenger service, it fits well with the conssumption quoted in Ian Walmsley’s article.
Crossrail’s Emergency Power
If you look at Crossrail’s Class 345 trains, they are nine cars, with a formation of
DMSO+PMSO+MSO+MSO+TSO+MSO+MSO+PMSO+DMSO
All the Ms mean that eight cars are motored.
Suppose each of the motored cars have a battery of 75 kWh.
- This means a total installed battery size of 600 kWh.
- Suppose the nine-car train needs Ian’s Walmsley’s high value of 5 kWh per vehicle mile to proceed through Crossrail.
- Thus 45 kWh will be needed to move the train for a mile.
- Dividing this into the battery capacity gives the range of 13.3 miles.
If this were Crossrail’s emergency range on stored energy, it would be more than enough to move the train to the next station or place of safety in case of a complete power failure.
Trains Suitable For Onboard Energy Storage
I have a feeling that for any train to run efficiently with batteries, there needs to be a lot of powered axles and batteries distributed along the train.
Aventras certainly have a lot of powered axles and I think Hitachi trains are similar.
Perhaps this explains, why after the successful trial of battery technology on a Class 379 train, it has not been retrofitted to any other Electrostars.
There might not be enough powered axles!
Topping Up The Onboard Energy Storage
There are three main ways to top up the onboard energy storage.
- From regenerative braking.
- From the diesel or hydrogen powerpack.
- From the electrification, where it is available.
The latter is probably the most efficient and is ideal, where a route is partly electrified.
Affordable Electrification
Although the Government has said that there will be no more electrification, I think there will be selective affordable electrification to improve the efficiency of multi-mode trains.
Why Is Electrification Often Late And Over Budget?
The reasons I have found or been told are varied.
- Electrification seems regularly to hit unexpected infrastructure like sewers and cables on older routes.
- There have been examples of poor engineering.
- There is a large amount of Victorian infrastructure like bridges and stations that need to be rebuilt.
- There is a certain amount of opposition from the Heritage lobby.
- Connecting the electrification to the National Grid can be a large cost.
My experience in Project Management, also leads me to believe that although Network Rail seems to plan large station and track projects well, they tend to get in rather a mess with large electrification projects.
Electrification Of New Track
It may only be a personal feeling, but where new track has been laid and it is electrified Network Rail don’t seem to have the same level of problems.
These projects are generally smaller, but also I suspect the track-bed has been well-surveyed and well-built, to give a good foundation for the electrification.
It was interesting to note a few weeks ago at Blackpool, where they are electrifying the line, that Network Rail appeared to be relaying all of the track as well.
I know they were also re-signalling the area, but have Network Rail decided that the best way to electrify the line was a complete rebuild?
Short Lengths Of New Electrification
Short lengths of new electrification could make all the difference on routes using multi-mode trains with onboard energy storage.
As a simple example, I’ll take the Felixstowe Branch Line, that I know well. Ipswwich to Felixstowe is about sixteen miles, which is probably too far for a train running on onboard energy storage. But there are places, where short lengths of electrification would be beneficial to both the Class 755 trains and trains with onboard energy storage.
- Ipswich to Westerfield
- On the section of double-track to be built in 2019.
- Felixstowe station
There is also the large number of diesel-hauled freight trains passing through the area, quite a few of which change to and from electric haulage at Ipswich.
So would some selective short lengths of electrification enable the route to be run by trains using onboard energy storage?
Electrification Of Tunnels
Over the last few years, there has been some very successful electrification of tunnels like the seven kilometre long Severn Tunnel. This is said about the problems of electrification in Wikipedia.
As part of the 21st-century modernisation of the Great Western Main Line, the tunnel was prepared for electrification. It has good clearances and was relatively easy to electrify, although due to its age, the seepage of water from above in some areas provided an engineering challenge. The options of using either normal tunnel electrification equipment or a covered solid beam technology were considered and the decision was made to use a solid beam. Over the length of the tunnel, an aluminium conductor rail holds the copper cable, which is not under tension. A six-week closure of the tunnel started on 12 September 2016. During that time, alternative means of travel were either a longer train journey via Gloucester, or a bus service between Severn Tunnel Junction and Bristol Parkway stations. Also during that time, and possibly later, there were direct flights between Cardiff and London City Airport. The tunnel was reopened on 22 October 2016.
It appears to have been a challenging but successful project.
This type of solid beam electrification has been used successfully by Crossrail and Chris Gibb has suggested using overhead beam to electrify the three tunnels on the Uckfield Branch Line.
In the North of England, there are quite a few long tunnels.
Could these become islands of electrification to both speed the trains and charge the onbosrd energy storage?
Third-Rail Electrification Of Stations
Ian Walmsley in his Modern Railways article proposes using third rail electrification at Uckfield station to charge the onboard energy storage of the trains. He also says this.
This would need only one substation and the third rail could energise only when there is a train on it, like a Bordeaux tram, hence minimal safety risk.
There needs to be some serious thought about how you create a safe, affordable installation for a station.
I also feel there is no need to limit the use of short lengths of third-rail electrification to terminal stations. On the Uckfield Branch, some stations are very rural, but others are in centres of population and/or industry, where electricity to power a short length of third-rail might be available.
Overhead Beams In Stations
This picture shows the Seville trams, which use an overhead beam at stops to charge their onboard energy storage.
Surely devices like these can be used in selective stations, like Hull, Scarborough and Uckfield.
Third-Rail Electrification On Bridges And Viaducts
Some bridges and high rail viaducts like the Chappel Viaduct on the Gainsborough Line, present unique electrification problems.
- It is Grade II Listed.
- Would overhead electrification gantries be welcomed by the heritage lobby?
- It is 23 metres high.
- Would this height present severe Health and Safety problems for work on the line?
- The viaduct is 320 metres long.
Could structures like this be electrified using third-rail methods?
- The technology is proven.
- As in stations, it could only be switched on when needed.
- The electrification would not be generally visible.
The only minor disadvantage is that dual-voltage trains would be needed. But most trains destined for the UK market are designed to work on both systems.
Getting Power To Short Lengths Of Electrification
One thing that is probably needed is innovation in powering these short sections of electrification.
Conclusion
There are a very large number of techniques that can enable a multi-mode train to roam freely over large parts of the UK.
It is also a team effort, with every design element of the train, track, signalling and stations contributing to an efficient low-energy train, that is not too heavy.
?
Do Class 800/801/802 Trains Use Batteries For Regenerative Braking?
I ask this question, because I think that it could be key to the announcements about electrification yesterday, as reported in this article in Global Rail News, which is entitled UK Ditches Electrification Plans In Wales, The Midlands And The North.
If you look at all these Wikipedia entries for Hitachi trains being built for the UK.
You will find no reference to regenerative braking.
If you type “Class 800 regenerative braking” into Google, you will find this document on the Hitachi Rail web site, which is entitled Development of Class 800/801 High-speed Rolling Stock for UK Intercity Express Programme.
The only mention of the R-word is in this paragraph.
An RGS-compliant integrated on-train data recorder (OTDR) and juridical recording unit (JRU), and an EN-compliant energy
meter to record energy consumption and regeneration are fitted to the train.
If you search for brake in the document, you find this paragraph.
In addition to the GU, other components installed under the floor of drive cars include the traction converter, fuel tank, fire protection system, and brake system.
Note that GU stands for generator unit.
Traction System
I will start by having a detailed look at the traction system as described in the document.
The document provides this schematic of the traction system.
Note BC which is described as battery charger.
This is said in the text.
The system can select the appropriate power source from either the main transformer or the GUs. Also, the size and weight of the system were minimized by designing the power supply converter to be able to work with both power sources. To ensure that the Class 800 and 801 are able to adapt to future changes in operating practices, they both have the same traction system and the rolling stock can be operated as either class by simply adding or removing GUs. On the Class 800, which is intended to run on both electrified and non-electrified track, each traction system has its own GU. On the other hand, the Class 801 is designed only for electrified lines and has one or two GUs depending on the length of the trainset (one GU for trainsets of five to nine cars, two GUs for trainsets of 10 to 12 cars). These GUs supply emergency traction power and auxiliary power in the event of a power outage on the catenary, and as an auxiliary power supply on non-electrified lines where the Class 801 is in service and pulled by a locomotive. This allows the Class 801 to operate on lines it would otherwise not be able to use and provides a backup in the event of a catenary power outage or other problem on the ground systems as well as non-electrified routes in loco-hauled mode.
This is all very comprehensive.
But nothing is said about how regenerative brake currents from the traction motors are handled.
Any trained Control Engineer, of which I’m a life-expired example, can see all sorts of questions to ask.
- Could it be that all regenerative brake currents are fed into the Auxiliary Power Supply and then used for hotel power and to charge the battery?
- Is the generator unit switched on and off by a sophisticated control system, that uses GPS, train velocity, train weight, battery level etc.?
- Can battery power be used to move the train?
- How big is that mysterious battery?
In 2010, I wrote Edinburgh to Inverness in the Cab of an HST, after taking a memorable trip.
One memory of that trip is of the skill of the driver as he adjusted the twin throttles of the power cars and used the brakes, as the train travelled up hill and down dale.
This line will be Class 800 territory and I suspect that it will be worked by two five car units working as a ten-car train.
As I think that each five-car unit will have three generator units, does this mean that the driver will have six throttles?
Control Engineering has moved on in the forty years since the InterCity 125 entered service and I suspect that like an Airline Pilot, the driver of a Class 800 train, will have little control about how power is delivered. Except probably in a supervisory role.
So on routes like the Highland Main Line, the Class 800 will come into its own, using the generator units and stored energy as appropriate.
Obviously, the less the generator unit is used the better, as this minimises noise and vibration, and cuts carbon emissions.
Other features in the train design have been disclosed.
All Class 801 Trains Have At Least One Generator Unit
All Class 801 trains have at least one GU (generator unit), so it can obviously provide hotel power and probably enough power to limp to the next station, in case of overhead line failure.
Third Rail Class 800/801 Trains Are Possible
The layout of the traction system surely makes a third rail or even a dual-voltage version of the trains possible.
After all, their first cousin; the Class 395 train is a dual voltage train.
Locomotive Haulage Is Possible
As I said, the specification is comprehensive.
The document is also forthcoming in other areas.
Train Configuration
This is said.
Trains have a unit configuration of up to 12 cars, including the ability to add or remove standardised intermediate cars and the generator units (GUs)
(generators with diesel engines) needed to operate commercial services on non-electrified lines.
So if say GWR wanted an eleven-car train, it would be possible.
Automatic Coupling And Uncoupling
This is said.
Because the coupling or uncoupling of cars in a trainset occurs during commercial service at an intermediate station, the automatic coupling device is able to perform this operation in less than 2 minutes.
This is definitely in line with Class 395 train performance.
Automatic Train Identification Function
This is said.
To simplify the rearrangement and management of train configurations, functions are provided for identifying the train (Class 800/801), for automatically determining the cars in the trainset and its total length, and for coupling and uncoupling up to 12 cars in
normal and 24 cars in rescue or emergency mode.
I suspect most modern trains can do this.
One Twelve-Car Train Can Rescue Another
See the previous extract.
Flexible Interior Layout
This is said.
The rolling stock is designed to facilitate changes to the interior layout to accommodate changes to services or to the number of cars in the train.
I suspect that was expected.
An Interim Conclusion
In answer to the question, I posed with this post, I suspect that the answer is in the affirmative.
Extra Evidence
I also found this article on the Hitachi Rail web site, which is entitled Hybrid Propulsion with a sub-title of Energy-saving hybrid propulsion system using storage–battery technology.
This is the introductory paragraph.
As a step toward producing environmentally friendly propulsion systems, Hitachi has supplied a hybrid propulsion system that combines an engine generator, motor, and storage batteries. This system provides regenerative braking which has not been previously possible on conventional diesel-powered trains, and enables increased energy savings via regenerated energy.
They list the advantages as.
- 10% improvement of fuel consumption
- 60% reduction of the hazardous substances in engine exhaust
- 30db reduction of noise in stopping at the station
They also give various links that are worth reading.
All of these pages seem to have been published in 2013.
Conclusion
I will be very surprised if Class 800/801/802 trains don’t have batteries.
Looking at the schematic of the electrical system, the energy captured will at least be used for hotel power on the train.
Will the Class 385 trains for ScotRail have similar traction system?
Hitachi Class 385 Trains, Batteries And Charging Stations
This article in the International Railway Journal is entitled JR Kyushu battery EMU to enter service in October.
This is said.
JAPAN’s Kyushu Railway Company (JR Kyushu) announced on August 24 that its pre-series Dual Energy Charge Train (Dencha) battery-assisted EMU will enter revenue service on the 11km Orio – Wakamatsu section of the Chikuho Line on October 19.
The two-car 819 series set draws power from the 20 kV ac 60Hz electrification system to feed a bank of onboard batteries, which give the train a wire-free range of up to 90km.
At least it can do 11 km. This is said about the train’s manufacture.
The 819 series is based on the existing 817 series EMU and was built by Hitachi at its plant in Kudamatsu in Yamaguchi prefecture.
Note the word Hitachi!
Hitachi call it a BEC819 train and it is one of their ubiquitous A-trains.
On the Hitachi Rail Europe web site, three new trains are mentioned.
All are A-trains and on all pages, the word battery is mentioned under power supply.
So will Scotrail’s new Class 385 trains have a battery capability?
Probably not initially!
But Hitachi have obviously been doing a lot of research into battery trains and the JR Kyushu is the first practical application.
Scotland’s rail system outside Edinburgh and Glasgow is not electrified, but it is well-known that Scotland’s Government would like more electrified services and also links to places like Leven and St. Andrews.
Both of these places, and there are probably others as well, are a few miles from a main line, that is very likely to be electrified.
So could we see a battery train charged as the JR Kyushu train on a main line, serving these branch lines on battery power?
I feel that the chance of this happening is very high.
Put a charging station, like a Railbaar at the terminal station and it could be done as soon as the train is built.
Hitachi To Power Up Before Hinckley
This is the title of a small article in the Sunday Times, which talks about Hitachi’s plans to build a new nuclear power plant at Wylfa on Anglesey.
Hitachi would build a proven commercial reactor, that could be built by 2025.
Why are we bothering to still even think about the gold-plated Franco-Chinese dead elephant at Hinckley Point?
Hitachi is a private company and have to live from good designs, technology and engineering, whereas those behind Hinckley Point are governments or their agencies.
When you consider that the last big project of Hitachi in the UK, was to build a factory at Newton Aycliffe to construct trains and it would appear that that has gone to the plans, I suspect that going for Wylfa and putting Hinckley Point out of its misery, would be a pair of decisions, that have the much lesser risk.
The Anonymous Widower 