Train Fuel / Energy efficency

[Bringback309s]

Sorry this has probably been asked before but just thinking after seeing GWR getting their short HSTs together. How much fuel does, say, an HST use vs a short HST vs a sprinter? And how does the cost compare to electric? Can they be measured in MPG? (or GPM?)

 

[Llama]

Normal 2-car sprinter MPG on average runs is approx 2mpg (4mpg per vehicle). 156 units have a 400 gallon tank and a projected range of 1600 miles.

 

[sw1ller]

I believe the original design had a 1000 gallon tank with a 1400 mile range. So 0.7mpg over the two engines. But it’s had a new engine overhaul with better fuel efficiency since.

 

[bastien]

Full length HSTs do about 1mpg, so maybe a half length one going slower could double that?

 

[sw1ller]

Full length HSTs do about 1mpg, so maybe a half length one going slower could double that?

Is that at 125mph too? Would the scotrsil ones get to that speed? Don’t know the area at all.

 

[The Lad]

I depends slightly on how hard it is worked, stop/ start will use more. I seem to remember that if only one engine was working they couldn't do London - Inverness return without a top up.

 

[Bringback309s]

Full length HSTs do about 1mpg, so maybe a half length one going slower could double that?

Interesting, so the figures for a castle set vs sprinter look similar - and with the hills in the South West the HST should fare better. Seeing constantly overcrowded DMU's running whilst serviceable HST languish around in Cambridgeshire seems such a crying shame and all because of the PRM deadline. Using HST's "as is" should be quite acceptable to an average traveller who just wants a seat and to arrive on time. I'd rather an HST to most DMUs any day of the week!

 

[Richard Scott]

Seem to remember when the 150 and subsequent classes were built they were quoted as having fuel consumption of 6.6mpg per car; has this proved not to be the case?
Would be interesting to see what real life fuel consumption of various classes is i.e. is a small loco like a 25 much more fuel efficient than a larger one such as a 60 on the same load? How do the type 4s compare e.g. a 47 and a 50 and how does the two stroke (renowned for high fuel consumption at full power) in a 57 compare to a 47? If anyone has the data would be interested to know.
Also how will a 68 on load 5 compare to a 185 unit?

 

[yorkie]

Having larger, but fewer engines is likely to be more efficient than a greater quantity of smaller engines.

Also newer engines, such as the MTU engines in HSTs are typically going to be more efficient too.

 

[ac6000cw]

Some years ago, BR did some analysis of the 'whole life' (purchase+fuel+maintenance) costs of DMUs versus trains with the power equipment concentrated in one or two vehicles (loco hauled/HST). I think the crossover point was at about 7-8 coaches in length - so a full length HST was cheaper per seat than an equivalent length DMU, but shorter length versions were more expensive. So Regional Railways longer distance trains went DMU, and InterCity stayed HST and loco-hauled.

To compare short HST versus DMU running costs you'd have to measure both on exactly the same usage patterns (services/stopping patterns/speeds), otherwise you're comparing apples and oranges. Remember the two HST power cars weigh 140 tonnes alone (which you're dragging up the hills and accelerating away from stops and speed restrictions) - for a short 4 passenger-car HST that's 35 tonnes 'overhead' per passenger car (making each car weigh the equivalent of 70 tonnes, for comparison with a typical 23m DMU car of about 40 - 50 tonnes).

 

[squizzler]

Most of the aforementioned fuel consumption figures must, surely, be woefully out of date. In the motorcar scene we have got from about 30 -something mpg to about 60 in the past couple of decades, despite cars becoming lardier all round. The switch to diesel has made some difference, but in recent years petrol engined cars have made similar gains. Something like the class 172 or CAF 195s with traditional torque converters replaced by mechanical transmission and lightweight streamlined inside frame bogies must leave the older trains for dead in fuel economy. The train will have air conditioning and better soundproofing to add weight, but the car firms have had to incorporate these features too.

 

[Llama]

172s and 195s with their ZF mechanical transmissions don't coast freely like units with a Voith transmission such as 150, 156, 158, 170 etc, so although the 172/195 might be more efficient under power, that is eaten away on longer distances between stopping and starting by the fact a small amount of traction power has to be applied to maintain speed on falling gradients where a Voith unit would coast freely with no traction power applied.

 

[Llama]

Seem to remember when the 150 and subsequent classes were built they were quoted as having fuel consumption of 6.6mpg per car; has this proved not to be the case?

That is most likely going to have been continuous running rather than average daily diagrammed work of say 15-18 hours in service with 100-150 stops.

 

[sw1ller]

172s and 195s with their ZF mechanical transmissions don't coast freely like units with a Voith transmission such as 150, 156, 158, 170 etc, so although the 172/195 might be more efficient under power, that is eaten away on longer distances between stopping and starting by the fact a small amount of traction power has to be applied to maintain speed on falling gradients where a Voith unit would coast freely with no traction power applied.

This is very interesting. So will this save on brakes on long down hill sections I wonder?

 

[Llama]

The ZF gearboxes have a retarder, yes.

 

[ForTheLoveOf]

This is very interesting. So will this save on brakes on long down hill sections I wonder?

It was once pointed out to me that this is a false economy. Brakes are far easier and cheaper to replace than a gearbox, clutch, retarder etc. - certainly on most motor vehicles. Often these other means of deceleration are only used or fitted because the brakes don't suffice on their own.