The Anonymous Widower

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.
  • 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.

 

 

 

 

 

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October 7, 2017 - Posted by | Travel | , , , , , ,

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