The Anonymous Widower

Kinetic Energy Of A Five-Car Class 801 Train

The standard argument against the bi-mode Class 800 train, was that it would be lugging heavy diesel engines around the country wasting energy.

The Class 801 train is the all-electric version of the Hitachi train.

  • Wikipedia says each coach weighs 41 tonnes.
  • An empty five car train will therefore weigh 205 tonnes.
  • A five-car train seats 315 passengers.
  • If each passenger with baggage, bikes and buggies weighs 90 Kg, this mean they weigh 28.35 tonnes.
  • So the train has a weight of 233.35 tonnes.

Putting this figure into Omni’s Kinetic Engine Calculator gives a kinetic energy of 101.2 kWh.

Five-car Class 801 trains have one underfloor MTU 12V 1600 R80L diesel engine, which weigh seven tonnes, whereas the bi-mode Class 800 trains have three.

The engines have a rating pf 700 kW in the Class 802 trains and are derated to 560 kW in the other  two classes.

So adding engines and repeating the calculation gives.

  • One engine – 104.2 kWh
  • Two engines – 107.2 kWh
  • Three engines – 110.3 kWh

To accelerate a train with three engines to 125 mph will need an extra six kWh compared to a train with only one engine.

There will be a small acceleration penalty. But as three engines have a total power of 1,680 kW (Class 800) or 2,100 kW (Class 802), the penalty would be measured in seconds.

When the train is at the cruising speed of 125 mph, the only difference will be a two tonne difference in axle loading on some axles.

All Class 80x trains will have to overcome the same air resistance and provide similar hotel power., so I’m fairly certain, that all trains will consume very similar amounts of power in the cruise.

Power Comparison With An InterCity 125

Each Class 43 power car of an InterCity 125 has a single diesel engine rated at 1,700 kW.

Divide this by three and you get 566.7 kW

The de-rated MTU diesel engines in the Class 800 train are rated at 560 kW.

So did Hitachi look at the power of half an InterCity 125, feel that they could put diesel engines in three cars of a five-car train and then size the engines to get InterCity 125 power, with two trains working as a pair.

All they would then need to do is to design the cars of the new train to have aerodynamics, dynamics, performance and power usage as good or better than a forty-year-old train.

As they knew that the InterCity 125 had the capabilities needed for the routes, it would mean that their new train would perform, as required.

And if they needed more power for some routes, there was a 700 kW engine available.  Great Western Railway did need some more powerful trains and ordered thirty-six extra Class 802 trains with the larger engine.

If imitation is the sincerest form of flattery, the Japanese have been slowing tremendous respect to the InterCity 125.

Conclusion

It really is extraordinary, that the installed power of two five-car Class 800 trains, is little different to that of an InterCity 125.

The vindication is that both trains work well.

 

 

July 14, 2019 - Posted by | Transport | , ,

2 Comments »

  1. What’s wrong with SI units? – ~360MJ

    Comment by R. Mark Clayton | July 15, 2019 | Reply

    • Nothing! If I’m doing proper work, I ‘ve never used anything else .

      Comment by AnonW | July 15, 2019 | Reply


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