The Anonymous Widower

Are Alstom Going To Build All FLEXX Eco Bogies For The UK In Crewe?

The Zefiro 300 is a high speed train, that was built by a consortium of Bombardier and Hitachi Rail in Italy.

This is said in the Wikipedia entry for the Zefiro 300.

An evolution of the Italian version of the Zefiro 300 was also offered by Bombardier (joined with Hitachi Rail) for High Speed 2 commercial tender.

Note that the Zefiro 300 uses FLEXX Eco bogies.

Aventras also use these bogies, as do some other Bombardier trains in the UK, like Class 172 trains.

In The Value of Research, I said this about FLEXX Eco bogies.

Sad though, that although design is still in the UK, the bogies are now made in Germany. Here‘s the brochure.

The brochure link doesn’t work anymore.


I think it would not be a bad commercial and operational decision by Alstom to build and maintain all FLEXX Eco bogies for the UK in one factory at Crewe.

December 10, 2021 Posted by | Transport/Travel | , , , , , , , | 2 Comments

HS2 Ltd Awards Landmark Rolling Stock Contracts To Hitachi-Alstom Joint Venture

The title of this post, is the same as that of this press release from High Speed Two.

The press release gives two major bullet points.

  • Major boost for UK train-building as HS2’s state-of-the-art fleet of 225mph (360km/h) high speed trains will be built by Alstom and Hitachi Rail at their factories in County Durham, Derby and Crewe
  • Landmark contract set to support 2,500 jobs across the UK and boost the economy by over £157m each year

The press release then gives a link to this video clip.

The video doesn’t appear to show much.

These are my thoughts.

The Train Specification

This document on the Government web site is the Train Technical Specification for High Speed Two Classic-Compatible Trains.

The Bare Bones Of The Contract

These three paragraphs in the press release outline the contract.

HS2 Ltd today confirmed that a Hitachi/Alstom JV has been awarded the contracts to build Britain’s next generation of high speed trains at their factories in Derby and County Durham in a major deal set to support 2,500 jobs across the UK.

The landmark contracts – worth around £2bn – will see the JV design, build and maintain a fleet of 54 state-of-the-art high speed trains that will operate on HS2 – the new high-speed railway being built between London, the West Midlands and Crewe.

Capable of speeds of up to 225mph (360km/h), the fully electric trains will also run on the existing network to places such as Glasgow, Liverpool, Manchester and the North West. Building on the latest technology from the Japanese Shinkansen ‘bullet train’ and European high-speed network, they will be some of the fastest, quietest and most energy efficient high-speed trains operating anywhere in the world.

The third paragraph is probably the most significant, with the last few words standing out.

They will be some of the fastest, quietest and most energy efficient high-speed trains operating anywhere in the world.

That is a high bar and let’s hope the joint venture achieves it.

The Fastest Trains?

In Wikipedia’s section on High Speed Rail, this is said.

China has the fastest conventional high-speed rail in regular operation, with the Beijing–Shanghai high-speed railway reaching up to 350 km/h (217 mph).

It may not be the fastest, when it opens, but the Hitachi/Alstom JV train will certainly put the wind up the Chinese.

The Quietest Trains?

In Class 345 Trains Really Are Quiet!, which I wrote in May 2017, I said this.

This morning I was sitting waiting on Platform 8 at Stratford station.

Platform 8 is separated from Platform 9 by just two tracks, so you notice a train, when it goes through Platform 9 at speed.

Usually, the trains that go through Platform 9 at speed towards Liverpool Street station are Class 321 trains or rakes of Mark 3 coaches oulled by a Class 90 locomotives.

Today, a new Class 345 train went through and the level of noise was extremely low compared to other trains.

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.

I have since confirmed the quietness of Aventras many times.

I know the Aventra is only a suburban trundler, but have the JV applied all the knowledge that makes an Aventra such a quiet train to their new high speed train.

One of the best ways to cut noise on a vehicle or train, is to make sure all the components are as quiet as possible.

On a train, a surprising amount of high-frequency noise comes from the pantograph.

This article from Rail Technology Magazine is entitled HS2 Ltd Awards Hitachi-Alstom JV Landmark Rolling Stock Contracts. This is said about the pantograph.

The new trains will utilise a pioneering low noise pantograph, the arm which collects power from the overhead wires developed by Hitachi Rail. The technology was first developed in Japan and will make the new HS2 trains quieter than comparable high speed trains.

There’s nothing wrong with that logic.

The Most Energy Efficient Trains?

There are several clues to the energy efficiency of these trains.

The Rail Technology Magazine article also says this.

Regenerative braking to boost energy efficiency.

Nothing is said about whether the energy is returned to the track in any of the articles on the train.

But in the specification for the train, in Section 7.3 Braking, this is said.

The Unit shall be capable of achieving this deceleration for any payload up to Normal
Payload (HDL) without regenerating to the 25kV power supply.

So what does the train do with the energy?

It must be stored on the train and reused to accelerate the train or provide hotel power, which means the train must have integrated battery storage.

This would contribute to the train’s energy efficiency.

Other factors, that would contribute are a lighter weight and good aerodynamics.




Relationship To The Zefiro 300

The Zefiro 300 is a high speed train, that was built by a consortium of Bombardier and Hitachi Rail in Italy.

This is said in the Wikipedia entry for the Zefiro 300.

An evolution of the Italian version of the Zefiro 300 was also offered by Bombardier (joined with Hitachi Rail) for High Speed 2 commercial tender.


  1. The Zefiro 300 uses FLEXX Eco bogies.
  2. The Zefiro 300 is a 300 kph train.
  3. The Zefiro 300  is called a Frecciarossa 1000 in Italy.

There is also a Zefiro 380 in China, which is a 380 kph train.

I’ve ridden one of these trains and describe it in Riding The Frecciarossa.

I think the High Speed Two trains will have level boarding.


The bogies are one of the most important parts of the train. Like the Zefiro 300, will the train have FLEXX Eco bogies?

This article on Global Railway Review is entitled FLEXX Eco: The Leading Lightweight Passenger Bogie Design and it gives details on the bogie and its history.

Some of the concepts were developed at British Rail Research and some were applied to the bogies of the legendary British Rail Mark 3 and Mark 4 coaches, which ride better than some of today’s trains.

The Rail Technology Magazine article says this about the bogies.

Further supporting the UK rail supply chain, all of the bogies for the new trains will be assembled and maintained at Alstom’s facility in Crewe – which is the first time since 2004 that both jobs have been done in the UK.

It sounds sensible to have one factory to assemble and maintain the bogies.

Will this factory also supply the bogies for Aventras, which are also FLEXX Eco?


The press release says this about assembly.

  • The first stages including vehicle body assembly and initial fit-out will be done at Hitachi Rail’s facility at Newton Aycliffe, County Durham.
  • The second stage of fit out and testing will be done at Alstom’s Litchurch Lane factory in Derby.


I find it interesting, how improvements in one area help another.

The JV has worked hard to perfect this design.



December 9, 2021 Posted by | Transport/Travel | , , , , | 21 Comments

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.

  1. Three or four passenger cars.
  2. A power-pack in the middle with up to four Deutz 16 litre V8 diesel engines.
  3. 25 KVAC overhead electrification capability.
  4. 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.


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.







June 30, 2018 Posted by | Transport/Travel | , , , , , | 2 Comments

Bombardier’s Plug-and-Play Train


The heart of any electric train is the electrical system that takes the electricity from the overhead wires or third rail and distributes it to the traction motors that actually power the train. If regenerative braking is fitted, then the same system also handles any electricity generated by braking.

So that is where I’ll start.

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-Iron batteries if required.

Bombardier have confirmed the wiring for onboard power storage to me.

So this could mean, that if the overhead wire or third rail can’t accept electricity generated by regenerative braking, then if batteries are fitted, these can store the energy for reuse, and there will be an energy saving. With a commuter train doing frequent stops, the braking energy at a stop, copntributes to getting the train moving again.

If there is no way to recycle or store the braking energy, it is passed through resistors on the roof of the train, and used to heat the atmosphere.

If you look at just-released pictures of the Class 345 train, the trains appear to have the pantograph on one or more of the intermediate cars, unlike some electric multiple units which have them on the driving cars.

I did find this snippet on the Internet which gives the formation of the 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.

The snippet has a date of August 13th, 2016, so it’s very much up-to-date. It tells us the following.

  • All cars except one, have traction motors, which are responsible for both driving the train and providing a lot of the braking effort.
  • The pantograph car is motored, whereas on a Class 378 train it isn’t.
  • The only trailer car is in the middle of the train.
  • The train has two pantograph cars.
  • Would a pantograph car and one or more motor cars work together as was described in the Global Rail News article?

One of the big differences between the Aventra and the previous generation of Electrostar trains, is that many more cars are powered.

  • Distributing force along the train could be a very good way of applying greater total force to the track, to accelerate and brake the train faster.
  • Distributed power might be better in slippery rail conditions.
  • Splitting the power system between cars and using lighter-weight and better-designed FLEXX Eco bogies, may distribute the weight better along the train.
  • As there are more traction motors, does this mean they are smaller and possibly lighter and cost less.

I suspect that the distributed power approach has other advantages.

As the two pieces of information gleaned from the Internet are five years apart, I suspect that Bombardier have moved on from this concept of a pair of cars, one with the pantograph, third rail shoe and the converter and one with the energy storage.

I suspect that the electrical and motor systems of the Class 345 trains could be one of the following.

  • The whole train has a common power bus  and all motored axles are connected to it.
  • The train is effectively two half trains, each with their own power bus consisting of four cars in the following formation; DMSO+PMSO+MSO+MSO, with a trailer car without power in between.

These are my thoughts on the two approaches.

  • The second approach must have advantages in terms of reliability as there are two of everything.
  • The initial trains running from May 2017, will be seven cars, so will they be two three-car trains with a formation of DMSO+PMSO+MSO and a TSO in the middle? This would give a thorough test to all types of cars.
  • Going from seven to nine cars, just means adding an MSO to each half-train.
  • If necessary, Crossrail will lengthen trains to ten cars. Would they do this by adding another TSO?
  • The two pantographs must be at least a hundred metres apart, which could come in handy for jumping gaps in the overhead wires.
  • If the half-train approach is used, the two electrical buses would probably be connected together intelligently to share power.

So I wouldn’t be surprised to find, that the Class 345 trains are effectively two half trains working as one.

So how does a concept like this, fit with other train orders and lengths?

Class 710 Trains

The Class 710 trains for London Overground are four-car commuter trains, which will trundle around North-East London. I think they could have a formation of something like DMSO+PMSO+MSO+DMSO, which would fit the published information in the Global Rail News article of an electrical system based on at least two cars.

Incidentally, the five-car Class 378 trains with their three cars in the middle have two powered cars and a trailer car.

I said these trains will just trundle around London, but it would appear that all cars are powered, so I suspect they will accelerate away as fast as the track, passengers and the signals will allow.

As the braking is regenerative and either returns the braking energy to the overhead wires or stores it on the train, the trains will stop quickly and will be very efficient, with rapid stops at all stations.

Obviously, I can’t get any figure for how much time, the Class 710 trains will save say between Hackney Downs and Chingford, but I can show some figures on the eleven intermediate station Crossrail route between Stratford and Shenfield.

This currently takes 36 minutes in a Class 315 train and after Crossrail opens this will be 32 minutes in a Class 345 train.

So it looks like the new trains could save twenty seconds a stop. Not much, but the Shenfield Metro is probably running to a good speed.

Abellio’s Five Car Trains

These five-car trains could be two of the driving cars (DMSO) with a three-car set in the middle, so the formation could be DMSO+PMSO+MSO+MSO+DMSO or DMSO+PMSO+MSO+TSO+DMSO, depending on how much oomph was required.

Like the Class 710 trains, they would have a lot of powered axles and this helps create a specification including.

  • 100 mph capability.
  • Fast acceleration and braking.
  • An exceptional 100-0-100 mph time leading to extremely rapid stops.

They truly are pocket rockets.

Abellio’s Ten Car Trains

These ten-car trains will be similar to the five-car ones with a formation of something like.


where XXSO is anything that the operator wanted, but would normally be a MSO or a TSO.

Interim Conclusions On Aventras

I think I can draw some very important conclusions from what I have said already.

  • The Aventra is very different to an Electrostar.
  • The concept of having a sub-train of two or possibly three cars as outlined in the article in Global Rail News seems to work well with all of the trains ordered so far.
  • The sub-train probably wouldn’t include a driving car, as this would mean that in shorter trains, two types of driving can would be needed.
  • The driving cars could be identical except for the passenger compartment and the number of doors.
  • The overall design concept is very flexible.
  • All trains have a high proportion of motor cars and hence powered bogies, which probably means quick acceleration and good braking.
  • Train length can be filled out using additional motor or trailer cars.
  • Total train power can be adjusted by choosing the right mix of motor and trailer cars.

I shall now look at various topics in detail.

Train and Car Length

We know very little about the lengths of the cars in the various different Aventras, except these snippets from Modern Railways in September 2016 and some other sources.

  • Class 345 trains will have cars around 23 metres with three doors on either side.
  • Class 710 trains will have cars around 20 metres with two doors on either side.
  • The five-car Abellio East Anglia trains will be 110 metres long.
  • The ten-car Abellio East Anglia trains will be 240 metres long.

I suspect that  different car lengths and number of doors can be easily handled by a well-thought-out manufacturing process.

Much of the differences between the various fleets will come down to the interior design and equipment specified by the operator.

In The Aventra Car Length Puzzle, I came to the following conclusions.

  • The Aventra design is very flexible.
  • Driving cars generally seem to be around twenty metres.
  • There is an appropriate number of equal length intermediate cars between the two driving cars.

In some ways, it’s almost like a mini-HST.

And just like the HST and Bombardier’s successful Class 378 train for the London Overground, capacity and length is changed by just adding or removing intermediate cars.

I also stated in the related article, that Abellio’s five- and ten-car Aventras for East Anglia, could use these two basic car lengths.

  • A 20 metre driving car.
  • A 25 metre intermediate car.

My lengths might be wrong, but surely to have just two car types of the same size, gives a degree of design and operational flexibility , that must help the operator to a large degree.

In addition, if all driving cars are roughly the same size between the various Aventras, this must ease manufacture and support of the trains.

Different Driving Cars

First Class seats are expensive on space and fittings to provide and aren’t needed on all services.

If you take the selection of Abellio routes in East Anglia, that will be run exclusively by Aventras, how many destinations will actually need First Class seats?

  • Clacton, Frinton and Walton
  • Southend
  • Bishops Stortford and Hertford East

So as trains like the Class 360 trains have First Class at one end of the formation, will we see at least two types of driving car?

  • One with an appropriate number of First Class seats.
  • One which is all Standard Class.

I suspect that from the bulkhead behind the driver forward, all driving cars will be more or less identical with a few differences due to operator, route and signalling, but on the passenger side, the layout will be adjusted to the route.

We could even see quick change interiors in the small section of the driving car behind the driver.

After all airliners have been configured in this way for many years, with movable screens to separate Business seats from the riff-raff.

So could we see various configurations of the driving cars?

  • First Class
  • Standard Class
  • Mixed First and Standard Class
  • Bicycle Racks
  • Heavy Luggage and Parcel Space
  • Toilets
  • Buffets and shops.

Obviously, the train operator, would make sure that their driving cars were right for the routes they served.

Flexible Train Lengths

Bombardier seem to have possibly used the experience they gained with the Class 378 trains on the London Overground, which have progressively been lengthened from three to four and five-cars since delivery five years ago, just by adding extra intermediate cars.

I suspect that appropriate driving and intermediate cars can be shuffled together in order, to create any length of train from four-cars upwards.

I showed earlier, how the Cl;ass 345 trains could be adjusted as time progresses, so Abellio might benefit from a similar flexibility.

Abellio have ordered both five- and ten-car trains for their East Anglian routes, so could we see trains put into alternative formations, if that suits the route and passenger demand better?

Incidentally, I travel regularly on Virgin’s Pendolinos to the North West and these Class 390 trains have changed in length over the years.

They are a good example of future-proofing a train design, so that formations can change as the routes and requirements evolve.

Nothing would seem to prevent the length of an operator’s fleet of Aventra trains from being changed.

The Aventra Marketplace

I have just found this article in Rail Engineer from February 2014, which is entitled An Exciting New Aventra.

Jon Shaw from Bombardier is quoted as saying this about the market for the Aventra.

We looked ahead for ten years and spoke to potential stakeholders and customers, including the Department for Transport, as well as Transport for London, and all of the operators and train leasing companies and passenger focus groups, and they told us what they thought was going to happen over the ten years ahead. Essentially, four styles of train will be needed. One will be the dedicated metro trains, running all day at high capacity. Then there will be slow-speed and medium speed commuter trains, as we have today. Lastly, there is what we see as a new market, which is high speed commuters – they can serve a commuter market, but when they go onto that main line, they’re going to hit 125 mile an hour and so they don’t delay the main intercity trains.

So it looks like the four current orders fit these markets.

Aventras and Onboard Energy Storage

The article in Rail Engineer also quotes Jon Shaw 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.

I believe that once the concept of onboard energy storage is accepted, that Bombarduier’s engineers have found other ways to use it to the benefit of passengers, operators and Network Rail.

Aventras and Regenerative Braking

All Aventras have regenerative braking and of the various lines on which they will run, some will be able to handle the reverse currents.

However, other lines may not be able to handle regenerative braking.

If that is the case, then Aventras can be fitted with batteries or other forms of onboard energy storage to handle the braking.

There will obviously be a point where it is more affordable to handle regenerative braking on the train, rather than at the trackside.

Note that the energy generated from braking is easily calculated from the fomula for the kinetic energy in a moving object.

0.5 * (mass) * (velocity) * (velocity)

So stopping a train from 100 mph would release four times as much energy as from 50 mph. On starting again, a similar amount of energy would be need to be given to the train to regain line speed. If this is stored in the onboard storage of the train, then this must be able to hold the energy generated by one stop from the typical line speed.

It is not as onerous an application as actually driving the train for a few miles, as if more energy is needed to accelerate the train, the train will obtain it from the overhead wires or third rail.

The Full Aventra IPEMU

In the Rail |Engineer article Jon Shaw of Bombardier talked about a train with a fifty mile range on the onboard storage. He called it an independently powered EMU or IPEMU.

So what would a full Aventra IPEMU look like?

With sufficient onboard storage the four-car Class 710 train could be used as an IPEMU.  The storage would probably give a range similar to that of the Class 379 BEMU demonstration. This would mean the range is at least a one-way trip on the Mayflower Line, which is 11.3 miles or just under dozen miles.

This may not seem to be a very large range, but there are quite a few branch lines, where the out-and-back trip is less than or not much more than a dozen miles.

All connect or will in a couple of years to electrified main lines. Some even use a dedicated bay platform, which could be wired for charging.

The Mayflower Line is also a line, where the electrification has been simplified to save money.

Only one track is fully electrified and this restricts the services that electric trains can provide. However, if an Aventra IPEMU had a range of just a dozen miles, then with just some new track, possibly a set of points and no new electrification, services could be improved.

Other lines in this sorry or a neglected state include.

How many other Hall Farm Curves are there, where a short chord or line connects or could connect two electrified lines?

But as I said earlier, a dozen miles is a bit limiting. In Abellio’s East Anglia routes, these are the out-and-back distances for some lines.

There might also to be less than 25 miles of line without electrification between Haughley Junction and Cambridge.

Looking at these distances, an Aventra IPEMU with a range of greater than 25 miles would be a lot more useful.

But Jon Shaw of Bombardier is quoted in the article in Rail Engineer  of saying this.

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.

So what is available to increase the range?

My original musings in this section started with a four-car Class 710 train. But supposing we started with a five-car Aventra similar than those that have been ordered by Abellio for East Anglia.

The train could have this formation.


If both MSO cars had onboard energy storage, it would be a pocket rocket with a minimum range of at least 24 (2×12) miles on batteries!


  1. Are two cars with onboard energy storage needed to get sufficient range from the Aventra IPEMU?
  2. Two cars with onboard energy storage are obviously better than one!
  3. It would appear that the definitive Aventra IPEMU is a five-car train.
  4. The 50 mile range quoted by Jon haw could be available through better and larger storage technology.

As a trained control engineer, I know that balancing and controlling all these energy sources and sophisticated traction motors in an efficient and reliable manner will be very much possible and very rewarding for the engineers.

Aventra Is A Smart Train

This article in Rail Magazine is entitled Rise Of The Smart Train

It describes how trains can report faults remotely and make them easier and quicker to service. There is particular mention of Bombardier and the Class 710 trains.

Who is generally responsible for the servicing of a new fleet of trains?

These days maintenance is usually bundled into the lease contract. So a good train manufacturer can make more profits by making maintenance of a train easier and faster.

The smartness is not just about maintaining tracks.

This is from another article in Rail Magazine.

The trains have overhead line monitoring as a standard feature, and track monitoring equipment is also standard. So the operators don’t need to come and ask us to include it – it’s part of the build now.” That can help Network Rail identify, and fix, any problems much quicker.

When will cars report potholes?

There is also this snippet from this article in the Derby Telegraph

The train is also fitted with a “driver assistance system”, which takes into account gradients and route conditions to minimise power consumption.
Trials of the system, using a Class 365, brought a 13% energy saving, Bombardier said.

That could mean a saving in energy costs for the operator or extra range if running on the onboard energy storage.

Aventras Can Be Woken Up By Remote Control

This is discussed in Do Bombardier Aventras Have Remote Wake-Up?.

Regenerative Braking, Onboard Energy Storage And Current Orders

Nothing has been said about how any of the Aventra orders for London and East Anglia will use their regenerative braking, or whether the trains will be fitted with onboard energy storage.


I will consider Crossrail and the Class 345 trains first.

  • The contract for the trains was signed in February 2014 after the article in Global Rail News was published in March 2011.
  • This page on the Crossrail web site, says that trains will return braking energy to the grid.
  • Only Class 345 trains will use the Crossrail tunnels.
  • The Western surface section would be served by a variety of trains.
  • The Shenfield branch would probably only be served by Aventras.
  • The Abbey Wood branch would only be served by Class 345 trains.
  • Trains with onboard energy storage would have a limited recovery capability to travel to the next station, in case of an overhead line power failure.
  • If the trains  were fitted with onboard energy storage, the Old Oak Common depot could have less overhead wires, with positive cost and safely implications.

I think it is also true to say that other advantages apply, if the Crossrails tunnels and trains have been designed as an integrated system.

But I can’t find anything about how regenerative braking will be handled on London’s new line.

I wouldn’t rule out that all Class 345 trains were fitted with some form of onboard energy storage.


These statements will apply to the Class 710 trains, which will run on the London Overground.

  • Some of the electrification on the lines on which the Class 710 trains will run probably needs refurbishment and updating to accept the current flows from regenerative braking.
  • Will the Gospel Oak to Barking Line be electrified for regenerative braking? I suspect yes, as some electric locomotives will have regenerative braking in the future.
  • An IPEMU-capability that handled regenerative braking and gave a range of a dozen miles could be easily fitted to a Class 710 train.
  • Two Class 710 trains with an IPEMU-capability could  run a four trains per hour (tph) service on the  Greenford Branch, if this branch became part of London Overground.
  • Two Class 710 trains with an IPEMU-capability could  run a 4 tph service on the  Romford to  Upminster  Line with the reinstatement of a passing loop.
  • Class 710 trains with an IPEMU-capability could use a Hall Farm Curve without electrification to run between Chingford and Walthamstow to Lea Bridge and Stratford.
  • The Class 710 trains will use extended depots at Willesden and Ilford, so being able to be stored and run on lines without electrification could be an advantage.
  • Currently some trains are stabled overnight at Chingford. Would remote wake-up be used?
  • There may be places, where electrification can be simplified, if all trains had an IPEMU-capability.

A possible advantage is that the short extension to Barking Riverside could be built without electrification, as the length is well within the range of a Class 710 train with an IPEMU-capability.

Logic suggests that all Class 710 trains will have some onboard energy storage.


When considering the five- and ten-car trains for Abellio’s East Anglian routes, I think they can be thought of as several separate fleets for different routes.

  • ten-car trains without onboard energy storage.
  • ten-car trains  with enough onboard energy storage to handle regenerative braking, remote wake-up and limited movement without power.
  • five-car trains without onboard energy storage.
  • five-car trains with enough onboard energy storage to handle regenerative braking, remote wake-up and limited movement without power.
  • five-car trains with enough onboard energy storage to handle a 25 mile trip using the onboard energy storage.

I very much believe that because of the regenerative braking, overnight stabling and other issues, that all trains will have at least one MSO car equipped with onboard energy storage.

So we are left with the following train types.

  • ten-car trains  with enough onboard energy storage to handle regenerative braking, remote wake-up and limited movement without power.
  • five-car trains with enough onboard energy storage to handle regenerative braking, remote wake-up and limited movement without power.
  • five-car trains with enough onboard energy storage to handle a 25 mile trip using the onboard energy storage.

This effectively means there is an efficient ten-car train with some onboard energy storage for the following routes.

  • London to Southend
  • London to Clacton
  • London to Colchester
  • London to Ipswich – If still required.

Would the ten-car trains need one set of onboard energy storage or two?

An efficient five-car train with some onboard energy storage could be used on less busy routes.

  • London to Braintree
  • Witham to Braintree. – Shuttle using energy storage.
  • London to Harwich
  • Manningtree to Harwich. – Shuttle using energy storage.
  • London to Walton
  • Thorpe-le-Soken to Walton. – Shuttle using energy storage.
  • Stratford to Bishops Stortford
  • London to Bishops Stortford.
  • London to Hertford East.

What is interesting is that for the Braintree, Harwich and Walton route, the same trains can be used as direct trains to London or a shuttle to the main line station. All these branches probably need a bit of work to accommodate a second train.

Does this mean that all stations on the branch can have a 2 tph service to the main line and a 1 tph service to London?

The following routes will  need a five-car train with enough onboard energy storage for a 25 mile range.

  • Crouch Valley Line
  • Gainsborough Line
  • Felixstowe Branch
  • Cambridge to Ipswich

All services could go to 2 tph if required.

So it would appear that all trains will have at least one set of onboard energy storage and some five-car trains will have two sets to do the longer routes without elerctrification.


I’m fairly certain that all Aventras will use onboard energy storage for the following reasons.

  • If the train is fitted with remote control wake-up, some onboard power is needed to get the train ready.
  • Onboard energy storage allows depots and stabling sidings to be without overhead wires to save costs and increase safety.
  • Onboard energy storage handles the regenerative braking of the train.
  • Onboard energy storage can be used to move a train to safety after overhead line or third rail failure.

Even a small amount of onboard energy storage can move the train a few miles or so.

But if this analysis shows one thing, it is how a philosophy based on a series of standard coaches are just connected  together to create such a variety of trains, for such different purposes.

From the three train fleets ordered so far we have.

  • A  nine-car people carrier for 1,500, that can be any length from seven to ten-cars.
  • A four-car suburban runabout, in two variants with different power and seating.
  • A ten-car fast long distance train, that can take large numbers of commuters to and from work.
  • A five-car version of the ten-car long distance train, for thinner routes.
  • A five-car fast long-distance train, that can also travel independently for perhaps twenty-five milsl.

The Aventra really is true plug and play.








September 2, 2016 Posted by | Transport/Travel | , , , , , | 5 Comments

More On Class 345 Trains

In an article in this month’s Modern Railways, which is entitled 345 Counting On It, Ian Walmsley gives more details of the new Class 345 trains for Crossrail.

Ian uses phrases like.

Let’s get this out of the way first before I start enthusing (and I will) – personally I don’t like the interior colours.

Now I will go into full enthusing mode,

The bogies are the FLEXX Eco Bogie B5000-derivative inside-frame design similar to that on the Meridian (probably the only good thing about Meridians in my view)

The bodyshell is brilliant, and I say this as a passenger and an engineer.

The train is a fine piece of work.

He finishes by saying that he thinks the train will be a success for Bombardier.

Ian also throws in a few clues as to where Aventras might end up.

The 125 mph Aventra

Apparently, 125 mph Aventras are a possibility.So we could see High Speed Trains with similar performance to an InterCity 125, based on a train originally designed for commuters across London.

The High Speed Train With Batteries

One thing that Ian doesn’t mention about the Class 345 trains is whether they will be fitted with onboard energy storage. But he does say this.

Most braking will be done electrically, regenerating power to the grid.

So the answer is probably no! But it should be noted that Bombardier have told me that all Aventras are wired to accept onboard energy storage.

This raises the interesting possibility of the High Speed Train running on batteries.

I think that this could be a surprisingly large market.

Think of the routes which consist of two types of line.

  • A high speed electrified line, which permits trains to travel at 100-125 mph.
  • A secondary or branch line without electrification, that is up to about forty or fifty miles long.

On a quick look, I can think of these routes.

  • London Liverpool Street – Ipswich – Lowestoft
  • London Liverpool Street -Norwich – Yarmouth
  • London Kings Cross – Bradford
  • London Kings Cross – Harrogate
  • London Kings Cross – Huddersfield
  • London Kings Cross – Hull
  • London Kings Cross – Lincoln
  • London Kings Cross – Perth
  • London Kings Cross – Sheffield
  • London Kings Cross – Sunderland
  • London St. Pancras – Hastings – Eastbourne – Brighton
  • London Euston – Blackpool
  • London Euston – Chester
  • London Euston – Huddersfield
  • London Euston – Shrewsbury
  • London Waterloo – Exeter

I am assuming that electrification is at 2016 mileage.

As electrification increases more and more routes will be possible using a High Speed Train with batteries to extend the route away from the main line.


Ian mentions Merseyrail as another target.

They would appear to be a good match to Merseyrail’s specification, that I wrote about in Is Liverpool Planning To Invade Manchester By Train?

  • Merseyrail are looking to buy energy-efficient trains.
  • Merseyrail stated in Modern Railways that they were seriously interested in having IPEMUs.
  • Merseyrail want to expend their network and routes to Preston, Manchester via Kirkby, Chester via the Halton Curve and Wrexham via the Borderlands Line are very IPEMU-friendly routes.
  • Merseyrail needs trains that are certified for working in tunnels.
  • Merseyrail needs trains that can work on both third-rail and overhead electrification, which the dual-voltage Class 710/2 Aventra trains for the London Overground can do.
  • Ian feels the train’s low weight could be enough to avoid sub-station upgrades.

In addition, the modular nature of the Aventra design means that Merseyrail could have a mixture of train lengths and voltages to optimise their procurement and operating costs.

East Midlands Trains

Ian says this about using Aventras for East Midland trains electrics.

As a 125 mph unit it would cope well with Corby commuters and the ‘Master Cutler’ crowd. – It is all about the interior.

I think there are other factors, that could be useful, if some or all of the trains were an IPEMU variant.

  • I think Corby could be reached from St. Pancras by an IPEMU using the existing electrification.
  • Running on batteries through the Derwent Valley World Heritage Site, might avoid tricky negotiations with the heritage lobby.
  • Services could be extended past the current terminals of Nottingham and Sheffield.

Using Aventra IPEMUs would enable a whole new method of railway electrification.

Starting from Bedford, the electrification would be performed northward and as each section was completed, the Aventras could reach twenty or thirty miles further.

So electric train services would arrive at a town earlier than by using traditional methods.


Ian finishes the article with.

With the new design, Bombardier can take them all on. I think we will see this product platform around for many years, capitalising on the succes of Electrostar, and who knows, maybe even exporting to Europe? 345 – count on it.

If Bombardier have the right product, why not?








March 24, 2016 Posted by | Transport/Travel | , , , , , | 1 Comment

The Technology That Enables The Aventra IPEMU

It is worth stating why it looks like the Aventra IPEMU looks so promising.

Steel Wheel On Steel Rail

The dynamics of this are well known and mean the following.

  • There is a very low rolling resistance.
  • As more weight is applied, the rolling resistance goes down.
  • A fully loaded train might use less energy than an empty one.

You can’t ignore the laws of physics.


The air resistance of something like a train rises with the square of the speed.

But by careful aerodynamic design, you can reduce this energy loss substantially.

An Artist's Impression Of A Proposed Aventra

An Artist’s Impression Of A Proposed Aventra

The picture shows the clean lines of an Aventa

FLEXX-Eco Bogies

Boring but the design saves energy.

Low Energy Interiors

Air-conditioning and door and lighting systems have made great strides in recent years on reducing energy consumption.

Improved Energy Storage

The Class 379 Demonstrator used batteries, as nothing else was available. Better technology for this application like large capacitors and flywheels may be better suited to a train.

Because of the steel wheel on steel rail advantage weight is not a problem.

I think in a few years time, trains will use KERS. Like Formula 1, only bigger! It will be more affordable than batteries, as it’s purely electro-mechanical!

Regenerative Braking

Regenerative braking can save large amounts of energy, with Class 390 Pendolinos reportedly saving seventeen percent. But these trains give their generated energy to the overhead lines, whereas an Aventra IPEMU will keep the energy for itself in the storage device, if there is capacity.

From an electrical engineering point of view, I do wonder if energy storage is the best way to handle the electricity generated by regenerative braking, as otherwise it might have to be converted to transmit it back into the overhead wire or third rail.

I can see a time coming, when all electric trains have regenerative braking and energy storage!

Lightweight Construction

This only helps in the acceleration of the train, so it may not be as important as it would seem, because of the steel wheel on steel rail advantage.

Could it be that one of the reasons a High Speed Train rides so well, is that it is built out of steel and is strong and heavy?

Automated Systems

Things like pantograph deployment will be automatic, thus meaning when the train needs to add power and there is an overhead wire, this will be connected to power the train or top up the battery.

Automatic Train Control

But the biggest automation will be in the driving of the train. As on the Victoria Line the driver will tell the train to start and then it will go automatically to the next station. The train will collect information from the timetable, signals, GPS and sensors determining things like weather and passenger load and be driven accordingly.

Planes have been flown like this for many years.


The range of sixty miles quoted for the Demonstrator could be exceeded by a wide margin.

September 28, 2015 Posted by | Transport/Travel | , , , , | 1 Comment

The Value of Research

Companies are always being castigated for not doing enough research, but in this month’s Modern Railways, an example is given which shows how valuable research can be to both the company’s balance sheet and the man on the Dalston train.

When I worked in simulation using the PACE 231-R at ICI, I seem to remember reading in the literature about the problems British Rail were having with freight trains derailing as the speeds got higher. To try to solve the problems, BR Research Centre at Derby, did extensive computer simulations of wheel dynamics and probably became those with the greatest knowledge in the subject in the world. According to Modern Railways, they were then asked to design a bogie for passenger trains, that was lighter, stronger and required less maintenance.

With all of the privatisation and selling off of the railways in the 1980s and 1990s, the design could have got lost, but it ended up being commercialised and fitted to quite a few trains , including the Networkers and CapitalStars for the London Overground. The deasign team is based in Doncaster and is now part of Bombadier.

If that was the end of the story, that would have been good.

But it gets better in that the next generation of German ICE trains will be using this technology.

This article in Rail Engineer explains a bit more. under advanced bogie design, there is this section.

Whilst ELECTROSTAR is the lightest EMU in the market, weighing in at an average of just 42 tonnes per car, AVENTRA promises to be 20% lighter. This is achieved in no small part thanks to the introduction of Bombardier’s FLEXX Eco inside-frame bogie. It was designed for the UK market as part of the pioneering ‘Advanced Suburban Bogie’ project in the early 1990s. Initially tested in prototype form for two years under Class 320 vehicles (in 1991-92 using trailer bogies) and subsequently under Class 466s using motor bogies, it remains the only lightweight high-performance bogie in the world on main line passenger services.
The FLEXX Eco has an extremely credible track record, having travelled 1.5 billion kilometres in the UK under Voyager, Meridian and, more recently, TURBOSTAR units. It has also been exported to Norway, with 122 bogies supplied to state operator NSB. In reducing overall vehicle weight, the bogie makes a significant contribution to the energy saving advantages of the AVENTRA. It is particularly stable at high speed – it has been tested to 275kph under a Japanese Shinkansen and 392kph beneath an ICE2 – and delivers excellent performance through curves.

So a little trumpeted small amount of money invested by British Rail has become a true success story, albeit totally hidden from the man on the Dalston train, unless he cares to look underneath a train in the station.

Sad though, that although design is still in the UK, the bogies are now made in Germany. Here‘s the brochure.

And here’s one of the bogies under a CapitalStar at Highbury and Islington Station.

FLEXX Eco Bogie Under a Capitalstar

I use these trains a lot and can confirm that the ride quality is up with the best.

May 30, 2011 Posted by | World | , , | 4 Comments