The Anonymous Widower

What Would Be The Ultimate Range Of A Nine-Car Class 800 Train?

In Thoughts On Batteries On A Hitachi Intercity Tri-Mode Battery Train, I had a section, which was called The Ultimate Battery Train.

I said this.

I think it would be possible to put together a nine car battery-electric train with a long range.

  • It would be based based on Hitachi Intercity Tri-Mode Battery Train technology, which would be applied to a Class 800 or Class 802 train.
  • It would have two driver cars without batteries.
  • It would have seven intermediate cars with 600 kWh batteries.
  • It would have a total battery capacity of 4200 kWh.
  • The train would be optimised for 100 mph running.
  • My estimate in How Much Power Is Needed To Run A Train At 125 Or 100 mph?,   said it would need 2.19 kWh per vehicle mile to cruise at 100 mph.

That would give a range of over 200 miles.

If the batteries were only 500 kWh, the range would be 178 miles.

Aberdeen, Inverness, Penzance and Swansea here we come.

Note that I have ignored energy lost in the station stops.

Energy Use And Recovery In A Station Stop

The station stop will be handled something like this.

The train will be happily trundling along at 100 mph.

At the right moment, the driver will apply the brakes and the train will stop in the station.

With trains like these Hitachi trains and many others, braking is performed by turning the traction motors into generators and the kinetic energy of the train will be turned into electricity.

Normally with this regenerative braking, the electricity is returned to the track, but these trains are not running on electrified track, so the electricity will be stored in the traction batteries on the train. This is often done in battery-electric road vehicles.

After the stop, the train will use battery power to accelerate back to 100 mph.

What kinetic energy will a Class 800 train have at 100 mph?

  • The basic weight of a nine-car Class 800 train is 438 tonnes.
  • I am assuming that the batteries are no heavier than the diesel engines they replace.
  • The trains hold 611 passengers.
  • I will assume each weighs 80 Kg with baggage, bikes and buggies, which gives a weight of 48.9 tonnes.
  • This gives a total train weight of 486.9 tonnes.

Using Omni’s Kinetic Energy Calculator, gives a kinetic energy of 135.145 kWh.

When I first saw figures like this, I felt I had something wrong, but after checking time and time again, they still appear.

At each stop a proportion of the train’s kinetic energy will not be recovered.

These figures show the extra energy needed at each stop with different regenerative braking efficiencies.

  • 100 % – 0 kWh
  • 90 % – 13.51 kWh
  • 80 % – 27.03 kWh
  • 70 % – 40.54 kWh
  • 60 % – 54.06 kWh

Obviously, the more efficient the regenerative braking, the less energy that needs to be added at each stop.

Edinburgh And Aberdeen

I am using Edinburgh and Aberdeen as an example.

Consider.

  • I am assuming the train is cruising at 100 mph along the route.
  • There are seven stations to the North of Haymarket station.
  • If I assume 60 % regenerative braking efficiency, then each stop will need 54.06 kWh of electricity from the batteries.
  • This gives a total of 378.4 kWh for the stops. Let’s call it 400 kWh.
  • This effectively reduces the usable battery size to 3800 kWh
  • Take off 200 kWh to make sure there’s always space for regenerative braking energy and useable battery size is 3600 kWh.

This can then be divided by the number of cars and 2.19 kWh per vehicle mile, to get the range.

This gives a range of over 180 miles.

With 500 kWh batteries the distance is just under 180 miles.

It certainly appears that a battery-electric train with seven 500-600 kWh batteries should be able to run between Edinburgh and Aberdeen.

Obviously, charging would be needed at Aberdeen.

What Would Be The Ultimate Range Of A Five-Car Class 800 Train?

What kinetic energy will a five-car Class 800 train have at 100 mph?

  • The basic weight of a five-car Class 800 train is 243 tonnes.
  • I am assuming that the batteries are no heavier than the diesel engines they replace.
  • The trains hold 302 passengers.
  • I will assume each weighs 80 Kg with baggage, bikes and buggies, which gives a weight of 25.6 tonnes.
  • This gives a total train weight of 268.6 tonnes.

Using Omni’s Kinetic Energy Calculator, gives a kinetic energy of 74.6 kWh.

I will now use Edinburgh and Aberdeen as an example.

Consider.

  • I am assuming the train is cruising at 100 mph along the route.
  • I am assuming that the three intermediate cars have 600 kWh batteries.
  • There are seven stations to the North of Haymarket station.
  • If I assume 60 % regenerative braking efficiency, then each stop will need 29.84 kWh of electricity from the batteries.
  • This gives a total of 208.9 kWh for the stops. Let’s call it 210 kWh.
  • This effectively reduces the usable battery size to 1590 kWh
  • Take off 100 kWh to make sure there’s always space for regenerative braking energy and useable battery size is 1490 kWh.

This can then be divided by the number of cars and 2.19 kWh per vehicle mile, to get the range.

This gives a range of over 136 miles.

With 500 kWh batteries the distance is around 110 miles.

It looks to me, that from these calculations that a nine-car train with battery packs in all the intermediate cars has a longer range than a five-car train with battery packs in all the intermediate cars.

What Would Be The Range Of a Five-Car Class 803 Train Equipped With Batteries?

What kinetic energy will a five-car Class 803 train have at 100 mph?

  • The basic weight of a five-car Class 803 train is 228.5 tonnes.
  • Three 600 kWh batteries could add 18 tonnes
  • The trains hold 400 passengers.
  • I will assume each weighs 80 Kg with baggage, bikes and buggies, which gives a weight of 32 tonnes.
  • This gives a total train weight of 278.5 tonnes.

Using Omni’s Kinetic Energy Calculator, gives a kinetic energy of 77.3 kWh.

As before, I will now use Edinburgh and Aberdeen as an example.

Consider.

  • I am assuming the train is cruising at 100 mph along the route.
  • I am assuming that the three intermediate cars have 600 kWh batteries.
  • There are seven stations to the North of Haymarket station.
  • If I assume 60 % regenerative braking efficiency, then each stop will need 30.92 kWh of electricity from the batteries.
  • This gives a total of 216.4 kWh for the stops. Let’s call it 220 kWh.
  • This effectively reduces the usable battery size to 1580 kWh
  • Take off 100 kWh to make sure there’s always space for regenerative braking energy and useable battery size is 1480 kWh.

This can then be divided by the number of cars and 2.19 kWh per vehicle mile, to get the range.

This gives a range of over 135 miles.

With 500 kWh batteries the distance is around 110 miles.

 

June 2, 2021 - Posted by | Transport | , , ,

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