HST fuel consumption

hexagon789 · 21 Mar 2020

Seeing as this has pretty much developed into a seperate thread, I thought I'd better split it off before it takes the ScotRail HST thread anymore off topic.

PG said:
Safe to assume that the figure for MTUs is lower then?

I seem to find suggestions it's 15% better, but also suggestions it's not. The VP185 was said to be 15% better, but once in service BR found it was actually about 7% because the Valentas were doing more work initially!

paul1609 said:
Both the figures I've quoted were from the RSSB Traction Energy Metrics Report which no longer seems to be on line.
I think this was most likely for the Valenta Engine but Im not sure. MTUs blurb says that the replacement engine could save 15% on the Valentas.
If I had to place a bet I'd go for the 2 +4 car HST running on both power cars using about 5 times the fuel of a 3 car 170.

I've seen the 15% quoted a few times, but it's not the only figure.

A 2+4 would use less fuel than 2+8 though.

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hexagon789 · 21 Mar 2020

BRX said:
Do you have a copy of that report?

The numbers don't seem to be in line with eg this report

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=2ahUKEwjh3dSm3KzoAhUYQkEAHdojBI4QFjACegQIBRAB&url=https://ora.ox.ac.uk/objects/uuid:cd7d3eb7-e57c-427d-9ec6-70da72389cce/download_file?safe_filename=Are%2Brailways%2Bclimate%2Bfriendly%2B-%2BGivoni%2BBrand%2BWatkiss%2B-%2Baccepted%2Bmanuscript.pdf&file_format=application%2Fpdf&type_of_work=Journal+article&usg=AOvVaw1dXSwr0SJFhGFHAG0rerCM

View attachment 75656
That's for CO2 emissions but it seems reasonable to assume they are broadly proportional to the amount of fuel burnt. Even if you were to assume that halving the length of an HST didn't produce a reduction in fuel consumption - so you'd be looking at a doubling per pass-km for the HST - the numbers would be c.115 per pass-km for HST vs c.72 for 170.

I saw that when I was googling earlier, but wasn't sure how to interpret that in relation to fuel consumption.

PG · 21 Mar 2020

hexagon789 said:
I seem to find suggestions it's 15% better, but also suggestions it's not. The VP185 was said to be 15% better, but once in service BR found it was actually about 7% because the Valentas were doing more work initially!

Depends also if the electrical equipment that the engine was connected to was the same otherwise it's difficult to get a direct comparison between a Valenta and a VP185.

At the end of the day though the in service figures are what really count regardless of what configuration of engine and electrical gubbins are mated.

hexagon789 · 21 Mar 2020

PG said:
Depends also if the electrical equipment that the engine was connected to was the same otherwise it's difficult to get a direct comparison between a Valenta and a VP185.

At the end of the day though the in service figures are what really count regardless of what configuration of engine and electrical gubbins are mated.

I thought the electrical equipment was unaltered?

Bosch91 · 22 Mar 2020

Not train related, however the organisation I work for have re engined their fleet of vessels with MTU engines and the fuel consumption has increased by approx 50 litres per hour.

Hard to carry out a direct comparison as the newer engines also develop more power and produce fewer harmful emissions.

Id imagine the paxman -mtu swap may be similar.

BRX · 22 Mar 2020

170s also have mtu engines. And older ones than the HSTs?

PG · 22 Mar 2020

Bosch91 said:
Not train related, however the organisation I work for have re engined their fleet of vessels with MTU engines and the fuel consumption has increased by approx 50 litres per hour.

Hard to carry out a direct comparison as the newer engines also develop more power and produce fewer harmful emissions.

Id imagine the paxman -mtu swap may be similar.

Going by my (non railway) experience with buses that holds true - more power and better for the environment but overall fuel consumption greater.

hexagon789 said:
I thought the electrical equipment was unaltered?

I don't know, just raised it as a possible reason why the two installations might not be directly comparable.

Green tractor · 22 Mar 2020

I seem to remember (I could be wrong though) that it was said the MTU engines would pay for themselves in 2 years purley based on reduced fuel consumption.

paul1609 · 22 Mar 2020

hexagon789 said:
Seeing as this has pretty much developed into a seperate thread, I thought I'd better split it off before it takes the ScotRail HST thread anymore off topic.

I seem to find suggestions it's 15% better, but also suggestions it's not. The VP185 was said to be 15% better, but once in service BR found it was actually about 7% because the Valentas were doing more work initially!

I've seen the 15% quoted a few times, but it's not the only figure.

A 2+4 would use less fuel than 2+8 though.

The 2 + 4 configuration is a weight saving of roughly 26% on a 2 + 7, I took that in to consideration for my 5x guesstimate.
The few percentage on engine efficiency isn't going to change the fact that compared to a 170 the HSTs are real gas guzzlers (or carbon emitters).

gimmea50anyday · 22 Mar 2020

hexagon789 said:
I thought the electrical equipment was unaltered?

It isn’t, apart from the engines own control electronics. However there are at least two different cooler groups from different manufacturers fitted to the HST fleet and two different traction motors which could also make an albeit small difference

BRX · 22 Mar 2020

The fuel consumption figures for HSTs that no-one is able to back up, except by referring to the RSSB report - the report is available here if you register.

https://catalogues.rssb.co.uk/Pages/research-catalogue/PB009708.aspx

I've had a look through it. I can't find any reference to HST fuel consumption per km in it. Can anyone tell me which page I should be looking at?

GLC · 22 Mar 2020

I’ve not been able to find the specifications for the exact engine used in an HST, but google gives me this, https://mtu-online-shop.com/print/3239961_MTU_Rail_spec_4000R54_St3B.pdf
Which is a match for the displacement and the series, but not the exact application in an HST.

Regardless, if we use the figures for the R64 variant, which is close in terms of power output, that gives us 201g/kWh at peak power. Since that table also states the R64 generates 2000kW at peak, that gives us 402,000g per hour at peak power. I’m aware that grams to litres can vary depending on atmospheric conditions, but a quick online calculator give me the figure of 472L for 402,000g if diesel. Since an HST has 2 of these engines, that gives us 944L/h for the full train. That is predicated on a full hour running at full power, which is not realistic, at least for the Scotrail HSTs

Now, for a comparison against a 170, I found these engine specs:
https://www.mtu-solutions.com/content/dam/mtu/download/applications/rail/16120356_Rail_Solutionguide.pdf/_jcr_content/renditions/original./16120356_Rail_Solutionguide.pdf

This document also, does not have an exact match for the engine that Wikipedia, but there are entries for floor mounted engines which produce 315kW, which Wikipedia gives as the power output of a 170 engine. The most efficient of these is on page 9, which we shall be charitable, and use for comparison. That gives us an upfront L/h value of 75.1L/h. A (Scotrail)170 has 3 of these engines, so that’s 225.3L/h at full power.

Overall then:
5364hp HST: 944L/h
1266hp 170: 225.3L/h

These figures have to be taken with some large grains of salt, as I’ve not used exact engine specifications, but I hope they are in the ballpark. In terms of Litres per hour per horsepower, they are almost identical, which given both engines were installed around the same time, gives me confidence they are accurate

For an operator like Scotrail, where an HST is used interchangeably with a 170, the HST will be spending much less (if any!) time at full power, the fuel consumption will of course be lower.

I’ve no idea about engines, but I know that for electronics, there is the concept of race to sleep. This is where a chip operates at its highest power/frequency to complete its work as quickly as possible, before returning to as low a power state it can manage. It’s more efficient to burn hot and quick than lean and slow for electronics. Perhaps the same applies for engines?

Of course the above might all be utter bobbins of a bored home working crayonista :lol:

Highland37 · 22 Mar 2020

hexagon789 said:
Seeing as this has pretty much developed into a seperate thread, I thought I'd better split it off before it takes the ScotRail HST thread anymore off topic.

I seem to find suggestions it's 15% better, but also suggestions it's not. The VP185 was said to be 15% better, but once in service BR found it was actually about 7% because the Valentas were doing more work initially!

I've seen the 15% quoted a few times, but it's not the only figure.

A 2+4 would use less fuel than 2+8 though.

Where did you see these figures? Who said the Vp185 was 15% better and when?

hexagon789 · 22 Mar 2020

gimmea50anyday said:
It isn’t, apart from the engines own control electronics. However there are at least two different cooler groups from different manufacturers fitted to the HST fleet and two different traction motors which could also make an albeit small difference

The ratings appear identical for Brush/GEC traction motors but the coolers could well affect fuel consumption.

hexagon789 · 22 Mar 2020

paul1609 said:
The 2 + 4 configuration is a weight saving of roughly 26% on a 2 + 7, I took that in to consideration for my 5x guesstimate.
The few percentage on engine efficiency isn't going to change the fact that compared to a 170 the HSTs are real gas guzzlers (or carbon emitters).

Diesel perhaps, but apparently they have a lowed carbon footprint, possibly because they carry far more passengers than a 170 as full length sets. A 2+4 will be worse in that respect.

paul1609 · 22 Mar 2020

GLC said:
I’ve not been able to find the specifications for the exact engine used in an HST, but google gives me this, https://mtu-online-shop.com/print/3239961_MTU_Rail_spec_4000R54_St3B.pdf
Which is a match for the displacement and the series, but not the exact application in an HST.

Regardless, if we use the figures for the R64 variant, which is close in terms of power output, that gives us 201g/kWh at peak power. Since that table also states the R64 generates 2000kW at peak, that gives us 402,000g per hour at peak power. I’m aware that grams to litres can vary depending on atmospheric conditions, but a quick online calculator give me the figure of 472L for 402,000g if diesel. Since an HST has 2 of these engines, that gives us 944L/h for the full train. That is predicated on a full hour running at full power, which is not realistic, at least for the Scotrail HSTs

Now, for a comparison against a 170, I found these engine specs:
https://www.mtu-solutions.com/content/dam/mtu/download/applications/rail/16120356_Rail_Solutionguide.pdf/_jcr_content/renditions/original./16120356_Rail_Solutionguide.pdf

This document also, does not have an exact match for the engine that Wikipedia, but there are entries for floor mounted engines which produce 315kW, which Wikipedia gives as the power output of a 170 engine. The most efficient of these is on page 9, which we shall be charitable, and use for comparison. That gives us an upfront L/h value of 75.1L/h. A (Scotrail)170 has 3 of these engines, so that’s 225.3L/h at full power.

Overall then:
5364hp HST: 944L/h
1266hp 170: 225.3L/h

These figures have to be taken with some large grains of salt, as I’ve not used exact engine specifications, but I hope they are in the ballpark. In terms of Litres per hour per horsepower, they are almost identical, which given both engines were installed around the same time, gives me confidence they are accurate

For an operator like Scotrail, where an HST is used interchangeably with a 170, the HST will be spending much less (if any!) time at full power, the fuel consumption will of course be lower.

I’ve no idea about engines, but I know that for electronics, there is the concept of race to sleep. This is where a chip operates at its highest power/frequency to complete its work as quickly as possible, before returning to as low a power state it can manage. It’s more efficient to burn hot and quick than lean and slow for electronics. Perhaps the same applies for engines?

Of course the above might all be utter bobbins of a bored home working crayonista

You need to take in to account weight. Two HST power cars (2 +0) weigh marginally more than a 3 car 170.
a 2 + 4 formation equates to approximately 6 cars of 170.

hexagon789 · 22 Mar 2020

paul1609 said:
You need to take in to account weight. Two HST power cars (2 +0) weigh marginally more than a 3 car 170.
a 2 + 4 formation equates to approximately 6 cars of 170.

Perhaps fuel consumption per seat would be a fairer comparison

paul1609 · 22 Mar 2020

hexagon789 said:
Perhaps fuel consumption per seat would be a fairer comparison

Fuel consumption per seat on a scotrail 2 + 4 HST is around 4 times that per seat on a 3 car 170

hexagon789 · 22 Mar 2020

paul1609 said:
Fuel consumption per seat on a scotrail 2 + 4 HST is around 4 times that per seat on a 3 car 170

Higher than I expected.

And for a 2+5 set?

paul1609 · 22 Mar 2020

How many s

hexagon789 said:
Higher than I expected.

And for a 2+5 set?

How many seats in the fifth coach?

hexagon789 · 22 Mar 2020

paul1609 said:
How many s

How many seats in the fifth coach?

Depends, if they follow the plan - 74; if they change to a TGS it could be anything from 61-67.

paul1609 · 22 Mar 2020

hexagon789 said:
Depends, if they follow the plan - 74; if they change to a TGS it could be anything from 61-67.

With an additional 74 seats it would be around x 2.89 more fuel per seat. Obviously these are all estimated theoretical figure based on average consumption in a 2007 report. Someone at Scotrail presumably has the actual fuel bills but at the end of the day you cant beat physics and these trains have a lot more power and weigh a whole lot more.
Interestingly in the dim and distant past there was a plan for HSTs to replace 159s on the West of England Line (London Waterloo to Exeter) in this case the plan was for 1 power car to haul 5 coaches with one coach being converted to a driving trailer. Presumably the single power car reduced the costs and fuel consumption.

Speed43125 · 23 Mar 2020

paul1609 said:
With an additional 74 seats it would be around x 2.89 more fuel per seat. Obviously these are all estimated theoretical figure based on average consumption in a 2007 report. Someone at Scotrail presumably has the actual fuel bills but at the end of the day you cant beat physics and these trains have a lot more power and weigh a whole lot more.
Interestingly in the dim and distant past there was a plan for HSTs to replace 159s on the West of England Line (London Waterloo to Exeter) in this case the plan was for 1 power car to haul 5 coaches with one coach being converted to a driving trailer. Presumably the single power car reduced the costs and fuel consumption.

Similar thing was planned for E&G shuttles, I'm guessing it was the same with IC unwilling to give up sets there as well?

gingertom · 23 Mar 2020

Speed43125 said:
Similar thing was planned for E&G shuttles, I'm guessing it was the same with IC unwilling to give up sets there as well?

IC had to give them up but a better (allegedly) use for them was found elsewhere, MML and GW to service the Cotswolds IIRC.

KevinTurvey · 23 Mar 2020

An old driver told me his simple rule of thumb when being worked hard was a gallon a minute for a type 2 and around double that for a type 4 loco, so roughly this would be;
1250hp = 60 gal / 270 litres per hour
2750hp = 120 gal / 540 litres per hour
The previous figures for the turbostar and HST make a reasonable comparison, given advances in technology.

BRX · 23 Mar 2020

And when not being worked hard?

paul1609 · 23 Mar 2020

BRX said:
And when not being worked hard?

Unfortunately in the Scotrail case they are being worked relatively hard because they are very heavy express trains working on what are at best semi fast services.

BRX · 23 Mar 2020

paul1609 said:
Unfortunately in the Scotrail case they are being worked relatively hard because they are very heavy express trains working on what are at best semi fast services.

I agree they are heavier, but from what I recall of the drivers' reports on the Scotrail HST thread, it is hardly ever necessary to apply full power. Just a couple of locations on the HML route if I remember right, and it's only for a short time. You can't escape physics but it seems implausible to me that they would use nearly ten times as much fuel as a 170, as was being implied previously. No one has been able to provide a source for those figures.

hexagon789 · 23 Mar 2020

BRX said:
I agree they are heavier, but from what I recall of the drivers' reports on the Scotrail HST thread, it is hardly ever necessary to apply full power. Just a couple of locations on the HML route if I remember right, and it's only for a short time. You can't escape physics but it seems implausible to me that they would use nearly ten times as much fuel as a 170, as was being implied previously. No one has been able to provide a source for those figures.

I'm the same, I accept they likely use more fuel but the difference seems too great between HSTs and 170s even appreciating the difference between them in simple terms of one being a high-speed 125mph express train and the other a 100mph regional train.

paul1609 · 23 Mar 2020

BRX said:
I agree they are heavier, but from what I recall of the drivers' reports on the Scotrail HST thread, it is hardly ever necessary to apply full power. Just a couple of locations on the HML route if I remember right, and it's only for a short time. You can't escape physics but it seems implausible to me that they would use nearly ten times as much fuel as a 170, as was being implied previously. No one has been able to provide a source for those figures.

The almost 10 x figure I quoted was for a 2+7 HST v 3 car 170 which isn't whats being used. My best guesstimate was x5 for a 2 +4 vice a 3 car 170 or around x4on a per seat basis. The per seat basis is worse because much of the increased seats are first class.
A 2+4 HST weighs around the same as a 6 car 170 but has 3358KW power vice 1890KW for 6 car 170. A 6 car 170 would have a lot more seats.
The HSTs are a vanity project for Scotrail to have an internal "Intercity" network but they certainly aren't green.

HST fuel consumption

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