The Anonymous Widower

Thoughts On The Actual Battery Size In Class 756 Trains And Class 398 Tram-Trains

A Freedom of Information Request was sent to Transport for Wales, which said.

Please confirm the battery capacity and maximum distance possible under battery power for the Tram/Train, 3 & 4 Car Flirts.

The reply was as follows.

The batteries on the new fleets will have the following capacities: –

  • Class 756 (3-car) Flirt – 480 kWh
  • Class 756 (4-car) Flirt – 600 kWh
  • Class 398 tram-trains – 128 kWh

I will now have thoughts on both vehicles separately.

Class 756 Trains

In More On Tri-Mode Stadler Flirts, I speculated about the capacity of the batteries in the tri-mode Stadler Flirts, which are now called Class 756 trains, I said this.

I wonder how much energy storage you get for the weight of a V8 diesel, as used on a bi-mode Flirt?

The V8 16 litre diesel engines are made by Deutz and from their web site, it looks like they weigh about 1.3 tonnes.

How much energy could a 1.3 tonne battery store?

The best traction batteries can probably store 0.1 kWh per kilogram. Assuming that the usable battery weight is 1.2 tonnes, then each battery module could store 120 kWh or 360 kWh if there are three of them.

I also quoted this from the July 2018 Edition of Modern Railways.

The units will be able to run for 40 miles between charging, thanks to their three large batteries.

Since I wrote More On Tri-Mode Stadler Flirts in June 2018, a lot more information on the bi-mode Stadler Class 755 Flirt has become available and they have entered service with Greater Anglia.

Four-car trains weigh around 114 tonnes, with three-car trains around a hundred. I can also calculate kinetic energies.

How Good Was My Battery Size Estimate?

These are my estimate and the actual values for the three batteries in Class 756 trains

  • My estimate for Class 756 (3- & 4-car) – 120 kWh
  • Class 756 (3-car) Flirt – 160 kWh
  • Class 756 (4-car) Flirt – 200 kWh

So have Stadler’s battery manufacturer learned how to squeeze more kWh into the same weight of battery?

In Sparking A Revolution, I talked about Hitachi’s bullish plans for battery-powered trains, in a section called Costs and Power.

In that section, I used Hitachi’s quoted figures, that predicted a five tonne battery could hold a massive 15 MWh in fifteen years time.

If Stadler can get the same energy density in a battery as Hitachi, then their battery trains will have long enough ranges for many applications.

Class 398 Tram-Trains

In Sheffield Region Transport Plan 2019 – Tram-Trains Between Sheffield And Doncaster-Sheffield Airport, I showed this map of the route the trams would take.

I also said this about the tram-trains.

The distance between Rotherham Parkgate and Doncaster is under twelve miles and has full electrification at both ends.

The Class 399 tram-trains being built with a battery capability for the South Wales Metro to be delivered in 2023, should be able to reach Doncaster.

But there are probably other good reasons to fully electrify between Doncaster and Sheffield, via Meadowhall, Rotherham Central and Rotherham Parkgate.

The major work would probably be to update Rotherham Parkgate to a through station with two platforms and a step-free footbridge.

Currently, trains take twenty-three minutes between Rotherham Central and Doncaster. This is a time, that the tram-trains would probably match.

If you adopt the normal energy consumption of between three and five kWh per vehicle mile on the section without electrification between Rotherham Parkgate and Doncaster, you get a battery size of between 108 and 180 kWh.

It looks to me, that on a quick look, a 128 kWh battery could provide a useful range for one of Stadler’s Class 398/399 tram-trains.

Class 398 Tram-Trains Between Cardiff Bay and Cardiff Queen Street Stations

The distance between these two stations is six chains over a mile,

Adding the extra bit to the flourish might make a round trip between Cardiff Queen Street and The Flourish stations perhaps four miles.

Applying the normal energy consumption of between three and five kWh per vehicle mile on the section without electrification between Cardiff Queen Street and The Flourish, would need a battery size of between 36 and 60 kWh.

Conclusion

The battery sizes seem to fit the routes well.

 

 

March 11, 2020 - Posted by | Transport | , , , , , ,

2 Comments »

  1. […] Thoughts On The Actual Battery Size In Class 756 Trains And Class 398 Tram-Trains, I quoted the reply to a Freedom of Information Request sent to Transport for Wales, which […]

    Pingback by Thoughts On Powering Electrification Islands « The Anonymous Widower | April 14, 2020 | Reply

  2. […] Thoughts On The Actual Battery Size In Class 756 Trains And Class 398 Tram-Trains, I say that four-car Class 756 trains will have 600 kWh of batteries and a range of 40 miles. I […]

    Pingback by Northern’s Battery Plans « The Anonymous Widower | April 20, 2020 | Reply


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