The Anonymous Widower

Could A 125 Mph Electric Train With Batteries Handle The Midland Main Line?

In Bombardier’s 125 Mph Electric Train With Batteries, I investigated a pure electric train based on Bombardier’s proposed 125 mph bi-mode Aventra with batteries.

It would have the following characteristics.

  • Electric power on both 25 KVAC overhead and 750 VDC third-rail.
  • Appropriately-sized batteries.
  • 125 mph running, where possible on electrification and/or battery power.
  • Regenerative braking using the batteries.
  • Low energy interiors and systems.

It would be a train with efficiency levels higher than any train seen before.

It would also be zero-carbon at the point of delivery.

An Example 125 mph Train

I will use the same size and specification of train, that I used in Bombardier’s 125 Mph Electric Train With Batteries.

  • The train is five cars, with say four motored cars.
  • The empty train weighs close to 180 tonnes.
  • There are 430 passengers, with an average weight of 90 Kg each, with baggage, bikes and buggies.
  • This gives a total train weight of 218.7 tonnes.
  • The train is travelling at 200 kph or 125 mph.

Travelling at 200 kph, the train has an energy of 94.9 kWh.

I will also assume.

  • The train uses 15 kWh per mile to maintain the required line speed and power the train’s systems.
  • Regenerative braking is eighty percent efficient.

I will now do a few calculations.

Kettering To Leicester

Suppose one of the proposed trains was running between St. Pancras and Leicester.

  • I’m assuming there are no stops.
  • In a year or two, it should be able to run as far as Kettering using the new and improved 25 KVAC overhead electrification.
  • The train would leave the electrification at Kettering with a full charge in the batteries.
  • The train would also pass Kettering as close to the line speed as possible.
  • Hopefully, the twenty-nine miles without electrification between Kettering and Leicester will have been updated to have the highest possible line speed, with many sections capable of supporting 125 mph running.

I can do a rough-and-ready calculation, as to how much energy has been expended between Kettering and Leicester.

  • Twenty-nine miles at 15 kWh per mile is 435 kWh.
  • The train has a kinetic energy of 94.9 kWh at 125 mph and twenty percent will be lost in stopping at Leicester, which is 19 kWh.

This means that a battery of at least 454 kWh will be needed to propel the train to Leicester.

Kettering To Sheffield

If the train went all the way without stopping between Kettering and Sheffield, the energy used would be much higher.

One hundred-and-one miles at 15 kWh is 1515 kWh.

So given that the train will be slowing and accelerating, we’re probably talking of a battery capacity of around 2000 kWh.

In our five-car example train, this is 400 kWh per car.

Kettering To Sheffield With Stops

The previous calculation shows what can be achieved, but we need a practical train service.

When I last went to Sheffield, the train stopped at Leicester, Loughborough, East Midlands Parkway, Long Eaton, Derby and Chesterfield.

I have built an Excel spreadsheet, that models this route and it shows that if the train has a battery capacity of 2,000 kWh, the train will get to Sheffield with 371 kWh left in the battery.

  • Increase the efficiency of the regenerative braking and the energy left is 425 kWh.
  • Reduce the train’s energy consumption to 12 kWh per mile and the energy left is 674 kWh.
  • Do both and the energy left is 728 kWh.

The message is clear; train manufacturers and their suppliers should use all efforts to improve the efficiencies of trains and all of their components.

  • Aerodynamics
  • \Weight savings
  • Bogie dynamics
  • Traction motors
  • Battery capacity and energy density
  • Low energy lighting and air-conditioning

No idea however wacky should be discarded.

Network Rail also has a part to play.

  • The track should have as a high a line speed as is practical.
  • Signalling and timetabling should be designed to minimise interactions with other services.

Adding all these together, I believe that in a few years, we could see a train, that will consume 10 kWh per mile and have a regenerative braking efficiency of ninety-five percent.

If this can be achieved then the train will have 960 kWh in the batteries when it arrives in Sheffield.

Sheffield To Kettering

There is no helpful stretch of electrification at the Sheffield end of the route, so I will assume that there is a method of charging the batteries at Sheffield.

Unsurprisingly, as the train is running the same total distance and making the same number of stops, if the train starts with a full battery at Sheffield, it arrives at Kettering with the same amount of energy in the battery, as on the Northbound-run to Sheffield.

An Interim Conclusion

I am led to the interim conclusion, that given the continued upward curve of technology and engineering, that it will be possible to run 125 mph electric trains with an appropriately-sized battery.

How Much Battery Capacity Can Be Installed In A Train?

In Issue 864 of Rail Magazine, there is an article entitled Scotland High Among Vivarail’s Targets for Class 230 D-Trains, where this is said.

Vivarail’s two-car battery units contains four 100 kWh lithium-ion battery rafts, each weighing 1.2 tonnes.

Consider.

  • Vivarail’s cars are 18.37 metres long.
  • Car length in a typical Aventra, like a Class 720 train, is 24 metres.
  • Aventras have been designed for batteries and supercapacitors, whereas the D78 trains, used as a base for the Class 230 train,were not.
  • Batteries and supercapacitors are getting better all the time.
  • Batteries and supercapacitors can probably be built to fit in unusually-shaped spaces.

I wouldn’t be surprised to see Aventras being able to take double the capacity of a Class 230 train under each car.

I wouldn’t rule out 2,000 kWh energy storage capacity on a five-car train, that was designed for batteries.

The actual size installed would depend on operator, weight, performance and cost.

My Excel spreadsheet shows that for reliable operation between Kettering and Sheffield, a battery of at least 1200 kWh is needed, with a very efficient train.

Charging Trains En-Route

I covered en-route charging fully in Charging Battery/Electric Trains En-Route.

I came to this conclusion.

I believe it is possible to design a charging system using proven third-rail technology and batteries or supercapacitors to transfer at least 200 kWh into a train’s batteries at each stop.

This means that a substantial top up can be given to the train’s batteries at stations equipped with a fast charging system.

An Astonishing Set Of Results

I use astonishing lightly, but I am very surprised.

I assumed the following.

  • The train uses 15 kWh per mile to maintain the required line speed and power the train’s systems.
  • Regenerative braking is eighty percent efficient.
  • The train is fitted with 600 kWh of energy storage.
  • At each of the six stations up to 200 kWh of energy can be transferred to the train.

Going North the train arrives in Sheffield with 171 kWh in the energy storage.

Going South the train arrives at Kettering with 61 kWh in the energy storage.

Probably a bit tight for safety, but surprising nevertheless.

I then tried with the following.

  • The train uses 12 kWh per mile to maintain the required line speed and power the train’s systems.
  • Regenerative braking is ninety percent efficient.
  • The train is fitted with 500 kWh of energy storage.
  • At each of the six stations up to 200 kWh of energy can be transferred to the train.

Going North the train arrives in Sheffield with 258 kWh in the energy storage.

Going South the train arrives at Kettering with 114 kWh in the energy storage.

It would appear that increasing the efficiency of the train gives a lot of the improvement.

Finally, I put everything, at what I feel are the most efficient settings.

  • The train uses 10 kWh per mile to maintain the required line speed and power the train’s systems.
  • Regenerative braking is ninety-five percent efficient.
  • The train is fitted with 500 kWh of energy storage.
  • At each of the six stations up to 200 kWh of energy can be transferred to the train.

Going North the train arrives in Sheffield with 325 kWh in the energy storage.

Going South the train arrives at Kettering with 210 kWh in the energy storage.

These sets of figures prove to me, that it is possible to design a 125 mph battery/electric hybrid train and a set of charging stations, that will make St. Pancras to Sheffield by electric train, a viable possibility without any more electrification.

Should The Train Be Fitted With A Means Of Charging The Batteries?

Why not?

Wires do go down and rest assured, a couple of battery/electric hybrids would get stuck!

So a small diesel or hydrogen generator to allow a train to limp a few miles might not be a bad idea.

Electrification Between Sheffield And Clay Cross On The Midland Main Line

In The UK’s New High Speed Line Being Built By Stealth, there is a sub-section with the same title as this sub-section.

This is the first part of that sub-section.

This article on Rail Technology Magazine is entitled Grayling Asks HS2 To Prepare For Electrification Of 25km Midland Main Line Route.

If this electrification happens on the Midland Main Line between Sheffield and Clay Cross, it will be another project in turning the line into a high speed route with a 200 kph operating speed, between London and Sheffield.

Currently, the electrified section of the line South of Bedford is being upgraded and the electrification and quadruple tracks are being extended to Glendon Junction, where the branch to Corby leaves the main line.

The proposed electrification will probably involve the following.

  • Upgrading the line to a higher speed of perhaps 225 kph, with provision to increase the speed of the line further.
  • Rebuilding of Chesterfield station in readiness for High Speed Two.
  • Full electrification between Sheffield and Clay Cross.

Clay Cross is significant, as it is where the Midland Main Line splits into two Southbound routes.

Note.

  1. Some of the tunnel portals in the Derwent Valley are Listed.
  2. Trying to electrify the line through the World Heritage Site will be a legal and engineering nightmare.
  3. Network Rail has spent or is spending £250million on upgrading the Erewash Valley Line.
  4. High Speed Two will reach The East Midlands Hub station in 2032.

When High Speed Two, is extended North from the East Midlands Hub station, it will take a route roughly following the M1. A spur will link High Speed Two to the Erewash Valley line in the Clay Cross area, to enable services to Chesterfield and Sheffield.

But until High Speed Two is built North of the East Midlands Hub station, the Erewash Valley Line looks from my helicopter to be capable of supporting 200 kph services.

If this electrification is performed, it will transform the prospects for battery/electric hybrid trains between London and Sheffield.

  • Trains will have to run fifteen miles less on battery power.
  • Trains will arrive in both St. Pancras and Sheffield with batteries that are at least three-quarters full.
  • Returning the trains will fill them up on the electrification at the end of the line.
  • There will probably not be a need for charging systems at St. Pancras, Chesterfield and Sheffield.

I also think, that as the train could arrive in Sheffield with a full battery, there is the possibility of extending services past Sheffield to Barnsley, Huddersfield and cLeeds, if the operator felt it was a worthwhile service.

Nottingham

Nottingham is just eight miles from East Midlands Parkway station, which is less distance than Derby.

So if the battery/electric hybrid trains can reach Derby from Kettering on Battery power, with some help from charging at Leicester and Loughborough, the trains can reach Nottingham, where charging would be installed.

Conclusion

From my calculations, I’m sure that an efficient battery/electric hybrid train can handle all current services on the Midland Main Line, with third-rail charging at intermediate stations.

I do think though, that if Sheffield to Clay Cross Junction is electrified in preparation for High Speed Two, that it makes the design easier and the economics a lot better.

It would also give Sheffield a genuine sub-two hour service to London, which would only get better.

 

 

November 1, 2018 - Posted by | Travel | , , , , , , , ,

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