Great Western Coffee Shop

Can anyone help me with miles per gallon (or gallons per mile  :-X ) figures for diesel trains - especially comparing the same trains at different speeds?   Ideally, I would love to know how much fuel a 125 burns on (say) a normal Paddington to Plymouth run, and how that would vary if it was limited to top speeds of (a) 125 m.p.h., (b) 100 m.p.h., (c) 75 m.p.h and (d) 50 m.p.h.  If anyone happens to know how much fuel would need to be burned in a power station to run a similar capacity electric train over the route at various speeds, that would be lovely to know too.

Seriously, I don't think this is easy data to find - any help much appreciated.

P.S.  Yes - I know the wires only go as far as Airport Junction ... I would be happy with Kings Cross to York figures  ;)

Got a feeling that an HST at full chat uses 1mpg. Will so some asking at a place that will know!

That will be a tremendous start ... and (pretty please) can you ask about lesser speeds?   Thanks!

Would it make much difference if it were fairly empty versus packed to the point no one else can get one?

it certainly would as would the use of different buffet cars due to weight.

Oops.. I obviously meant to type "no one else can get on"  ::)

The big problem is finding consistency in the figures:-

http://www.lpdu.lancs.ac.uk/research/download/Transport%20Energy%20Consumption%20Discussion%20Paper.pdf (http://www.lpdu.lancs.ac.uk/research/download/Transport%20Energy%20Consumption%20Discussion%20Paper.pdf)

http://www.cambridgeenergy.com/archive/2007-02-08/cef08feb2007kemp.pdf (http://www.cambridgeenergy.com/archive/2007-02-08/cef08feb2007kemp.pdf)

http://www.theccc.org.uk/pdfs/080521%20CCC%20rail%20submission.pdf (http://www.theccc.org.uk/pdfs/080521%20CCC%20rail%20submission.pdf)

Trowres is right about consistency. Very difficult to get 'proper' figures, which suggests to me that the figures are not as green as they ought to be. If they were, then the rail industry would be shouting loudly about their green credentials.

One of the things that the industry is not doing right concerns weight. Acceleration is a very important part of overall fuel consumption if you're doing regular stops as on FGW. The car industry has been reducing car weight over the last 20-odd years, as a way of reducing fuel consumption. Alas, the same is not true of trains.

An eight-car HST weighs 413.9 tonnes and has 480 seats (OK, there'll be a bit of variation in that depending whether we're talking high-density or not), which works out at 0.86 t/seat.

The same figure for some other stock works out at

Stock	Seats	Weight (t)	t/seat
125 mile/h dmus
HST	480	413.9	0.86
Adelante	268	260.5	0.97
Voyager (220)	188	185.6	0.99
Super-Voyager (221)	250	282.8	1.13
InterCity electrics
East Coast class 91 + 10 coaches	600	532.3	0.89
Eurostar	383	360.7	0.94
Pendolino	447	459.7	1.03
90/100 mile/h dmus
Turbo (166)	275	119.3	0.43
Class 170	190	134.6	0.71
Class 185	171	163.0	0.95

The figure for the Turbos is improved by the 2+3 seating that they've got. Even if you down-rated them to (say) 225 'real' seats, you'd still be achieving 0.53 t/seat.

In each category, you can see that weight/seat has been going up over the years (and with it, fuel consumption). The tilting Voyagers and First TransPennine's 185s are particularly poor performers.

It has been about 30 years since I did Rail Traction at collage from what I can remember the weight of pass angers in terms of fuel usage should be averaged out to "normal passenger density" the fugue is the mass of the average passenger (based on the fugues published by the National Statistics Office for the average persons weight) times a loading density which I think is a train 2/3 full.  I can remember doing calcs at the time changing the number of passengers it really has little effect on the fuel consumption what it does effect more is the rate of acceleration both getting going and stopping.

There was some interesting stuff about fuel consumption and the Northern 185s in I think a recent Modern Railways. Note they are also the heaviest in t/seat in Worcester Passenger's table.

They have a fuel  computer similar to modern cars, and also an automatic engine shutdown when the power is not required. Drivers are encouraged to drive in a way  to save fuel (whilst keeping time!).

The writer remarked that it was very pleasant to be in the coach when the engine shut down I think on a journey from Manchester to York or Leeds. He implied it was virtually all the way from the Summit  to York or Leeds.

Of course with an HST it would also depend on how many intermediate stops there were on a journey. Obviously a non stop run at line speed to Plymouth would use less fuel than a run with say 10 intermediate stops.

Also if via B&H it would be less than Bristol due to less 125 running.

I imagine the fuel consumption on the Slough, Reading, Oxford HST's is fairly horrenodus.

What Worcester Passenger's table shows is just how good BR was at keeping train weights down. The HST's 91's+Mark 4s and 166 all come out better than the newer stock in their class.

Plus the Mark 3s have proved to be extremely robust in several accidents.

I am aware that to put in an SSO (special stop order) on a HST costs around ^200, so that equates to about 120-130 litres.
It also takes 20 litres extra to accelerate from 120mph to 125mph (that is acceleration only, not the actual running) so I suspect the figures are pretty variable, depending on train type, load, gradient, acceleration, speed etc etc.

Some interesting figures there. It seems the more emissions figures I see the more I dislike the HS2 proposals, seems that HighSpeed rail should only be built if it can reduce air travel.

Anyway my question is more about the performance of the older trains, specificly acceleration/breaking distances for sprinter units (as I'm trying to get an idea of how long a section needs to be for it be to be worth upgrading linespeeds). Specificly, for 150s, 153s/155s, 156s and 158s I would like to know:

• The distance required to accelerate from 0 to 60mph
• The distance required to accelerate from 60mph to 75mph (therefore giving me the distance from 0 to 75 if I add them up)
• The distance required to accelerate from 75mph to 90mph (158 only obviously)
• The distance required to break from 90mph back down to 75, and from there to 60 and there to 0.

I would also be interested to know the minimum radius of curves required to reach these speeds.

Hope I'm not asking too much here. Thanks in advance if you can help with this.