Class 57s and 68s speculative drag use for Cross Country

[Philip]

How would a top & tail pair of class 57s or 68s hauling a Voyager set; with no Voyager engines running; and only one loco engine running, compare for fuel efficiency with anything between 4-10 Voyager engines running, as is the current situation?

If the loco-drag option would save fuel, do you think Cross Country should consider hiring 68s, or 57s to haul some Voyager sets, considering the cost of diesel now and that it seems Cross Country will be operating Voyagers for the forseeable future? I'm assuming both locos can couple up to Voyagers?

 

[JonathanH]

I'm assuming both locos can couple up to Voyagers?

68s can't couple to Voyagers as they have conventional couplings. It isn't clear that a 57/3 would be able to provide train supply to a Voyager, as they were set up to haul Pendolinos. A Pendolino and Voyager can couple mechanically but are unlikely to be able to couple electronically.

It is an interesting idea to try and make Voyagers into push-pull sets but I think it is probably a solution looking for a problem rather than something actually viable.

 

[CBlue]

57s and 68s can't do 125 mph so it's a non starter from the get go.

 

[The Planner]

How would a top & tail pair of class 57s or 68s hauling a Voyager set; with no Voyager engines running; and only one loco engine running, compare for fuel efficiency with anything between 4-10 Voyager engines running, as is the current situation?

If the loco-drag option would save fuel, do you think Cross Country should consider hiring 68s, or 57s to haul some Voyager sets, considering the cost of diesel now and that it seems Cross Country will be operating Voyagers for the forseeable future? I'm assuming both locos can couple up to Voyagers?

Would destroy the timetable.

 

[CBlue]

I'd imagine TOC’s hedge their diesel purchases anyway. Assuming they do, the price fluctuations in fuel wouldn't have as much of an effect as you'd think.

I also understand they use red diesel which doesn't attract fuel duty - so the price they pay is far lower than some other modes.

 

[Philip]

Eventually I think all diesel trains will be limited to 90-100mph, particularly after the first leg of HS2 opens. The cost and also the environmental factors about diesel will probably lead for a push towards something like this.

 

[CBlue]

So we can rule the 68s out due to couplers. There also aren't enough 57/3s to top and tail all the voyagers in use? You also score poorly for environmental factor with a 57, a two stroke diesel isn't what you'd call "clean" emissions wise. I know there's a love-in for loco haulage on here but in all honesty fitting new engines to the Voyagers would likely be easier!

Makes a change from OP trying to suggest attaching 37s to everything I guess

 

[The Planner]

Eventually I think all diesel trains will be limited to 90-100mph, particularly after the first leg of HS2 opens. The cost and also the environmental factors about diesel will probably lead for a push towards something like this.

Doubt it.

 

[Bald Rick]

How would a top & tail pair of class 57s or 68s hauling a Voyager set; with no Voyager engines running; and only one loco engine running, compare for fuel efficiency with anything between 4-10 Voyager engines running, as is the current situation?

Eventually I think all diesel trains will be limited to 90-100mph, particularly after the first leg of HS2 opens. The cost and also the environmental factors about diesel will probably lead for a push towards something like this.

A 5 car 221 is 283 tonnes
A 5 car 221 with 2 x Class 68s would be 453 tonnes
A 5 car 221 with 2 x Class 57s would be 551 tonnes

Have a think - which of these would be

a) the best for fuel consumption (and therefore best for emissions)
b) the best for vehicle leasing / maintenance / track access charges
c) the most cost effective?


I do find it interesting how you often manage to come up with ideas that are fundamentally impractical or deliver completely the opposite of what you set out as an objective.

 

[CBlue]

I do find it interesting how you often manage to come up with ideas that are fundamentally impractical or deliver completely the opposite of what you set out as an objective.

Quite. There is a fair gap between "speculative" and "silly". OP seems to have a bias towards the latter.

 

[Philip]

A 5 car 221 is 283 tonnes
A 5 car 221 with 2 x Class 68s would be 453 tonnes
A 5 car 221 with 2 x Class 57s would be 551 tonnes

Have a think - which of these would be

a) the best for fuel consumption (and therefore best for emissions)
b) the best for vehicle leasing / maintenance / track access charges
c) the most cost effective?


I do find it interesting how you often manage to come up with ideas that are fundamentally impractical or deliver completely the opposite of what you set out as an objective.

A) The top and tail option: one big 57/67/68 engine running would use less fuel than 5 fairly big Voyager engines all running; QSK19s are very thirsty engines. The latter two locos would also produce less emissions. I wouldn't be surprised if the 57 produced less on its own compared with 5 Voyager engines, as the 57s were reconditioned 25 years ago.

B) Voyagers on their own

C) Without the exact figures for the cost of fuel vs track access and maintenance, I couldn't say.

 

[CBlue]

I wouldn't be surprised if the 57 produced less on its own compared with 5 Voyager engines, as the 57s were reconditioned 25 years ago.

"Reconditioned" - so not new and therefore didn't need to comply with emissions regulations when they were fitted to the locos.

The Cummins QSK engines found in Voyagers were -new- almost 20 years ago and had to therefore comply with whatever the regulations were at the time.

Two stroke diesels are not what you would call clean running - as I understand it, the nature of their combustion cycle means they generate far more CO2 for example.

 

[Dr Hoo]

A) The top and tail option: one big 57/67/68 engine running would use less fuel than 5 fairly big Voyager engines all running; QSK19s are very thirsty engines. The latter two locos would also produce less emissions. I wouldn't be surprised if the 57 produced less on its own compared with 5 Voyager engines, as the 57s were reconditioned 25 years ago.

You've clearly done a lot of research to validate your thesis.

Any chance that you post your quantitative results to illustrate it?

Thanks in advance.

 

[Philip]

You've clearly done a lot of research to validate your thesis.

Any chance that you post your quantitative results to illustrate it?

Thanks in advance.

No need to be clever... I think it's pretty clear that 5 intercity DMU engines would use more fuel than 1 big locomotive engine. And a 68 would produce less emissions than 5 Voyager engines - much newer for a start. It has been reported here that 68s can't couple up to Voyagers, however, I think the base idea has merit. If a 125mph bi-mode loco could be developed with couplers to attach to Voyagers, 185s and 180s then I think the idea could and should be trialled.

 

[HamworthyGoods]

I think it's pretty clear that 5 intercity DMU engines would use more fuel than 1 big locomotive engine.

How so?
Don’t forget you are near on doubling the tonnage this engine(s) has to haul.

 

[Speed43125]

Hijacking the thread slightly, how does a 5 coach 221 compare with a tpe or Chiltern 68+5 set?

 

[Neptune]

No need to be clever... I think it's pretty clear that 5 intercity DMU engines would use more fuel than 1 big locomotive engine. And a 68 would produce less emissions than 5 Voyager engines - much newer for a start. It has been reported here that 68s can't couple up to Voyagers, however, I think the base idea has merit.

To make it actually clear could you produce some real figures to back up your claims for a change rather than a hunch to back up what is clearly, as evidenced by other posts, a barmy idea with little or no merit.

If a 125mph bi-mode loco could be developed with couplers to attach to Voyagers, 185s and 180s then I think the idea could and should be trialled.

There’s speculative and there’s silly. This falls in the latter camp. You’ve leapt from 57’s/68’s hauling voyagers to a new 125mph bi-mode locomotive hauling voyagers, 185’s and 180’s. So you obviously don’t listen to anyone else and have indeed expanded your idea at great expense to the economy at a time when we have every paper clip audited.

This to me has huge overtones of ‘because locomotive haulage’ rather than any real concerns for the environment. After all, how is a diesel locomotive less polluting than a 3 car 185 running in eco-mode.

 

[CBlue]

I hear there are some 769s and 230s going spare, maybe they could be used to tow the voyagers instead?

 

[RobShipway]

I hear there are some 769s and 230s going spare, maybe they could be used to tow the voyagers instead?

Problem is, that I don't think it would be very safe for the class 769 or 230s to try to be doing 125mph!

 

[Philip]

How so?
Don’t forget you are near on doubling the tonnage this engine(s) has to haul.

Because the locomotive engine is not so big that it is 5 times bigger than the intercity DMU engine. I don't have access to specific figures but I do know that the basic principle is the bigger the engine, the more fuel it uses. However, having 5 engines running at once would equate to more than one big locomotive engine running, hence the train would use more fuel.
It would give more use to these intercity DMUs beyond the predicted timespan, by converting them to coaching stock and potentially removing the engines completely. Loco haulage is not 'out of fashion' as some people like to think; TfW are introducing new LHCS, TPE have done recently and the new West Coast Trains have been using it for their specials.

== Doublepost prevention - post automatically merged: 22 Dec 2022 ==

This to me has huge overtones of ‘because locomotive haulage’ rather than any real concerns for the environment. After all, how is a diesel locomotive less polluting than a 3 car 185 running in eco-mode.

A doubt it is less polluting than a 3-coach 185 in eco-mode, but compared with a double 185 set with all engines running, or Voyager sets, I would think a modern loco is indeed less polluting.

 

[GC class B1]

Because the locomotive engine is not so big that it is 5 times bigger than the intercity DMU engine. I don't have access to specific figures but I do know that the basic principle is the bigger the engine, the more fuel it uses. However, having 5 engines running at once would equate to more than one big locomotive engine running, hence the train would use more fuel.

I think the main point you are missing is that the energy required to move the much heavy push/pull train would be proportionally greater than the lighter voyager train on its own. As the push/ pull train is getting on for double the weight of the voyager train on its own, the locomotive engines would need to be something like twice as efficient as the voyager engines to see any improvement in fuel costs. I suspect this is very unlikely.

 

[CBlue]

I'm unsure as to why @Philip asks these questions, given that just about every one of his replies either ignores points other posters raise if they don't fit his view, or just refutes other posters points without providing anything conclusive to actually back up his own statements. As other posters have stated above, there is speculative and then there is stupid. This is the latter and your refusal to properly engage with the discussion makes the whole thread rather farcical.

 

[Philip]

I think the main point you are missing is that the energy required to move the much heavy push/pull train would be proportionally greater than the lighter voyager train on its own. As the push/ pull train is getting on for double the weight of the voyager train on its own, the locomotive engines would need to be something like twice as efficient as the voyager engines to see any improvement in fuel costs. I suspect this is very unlikely.

I can see the point with older locomotives, but using 68s as an example (ignoring that they can't currently couple to Voyagers), these engines are 15 years newer than the Voyagers so their overall efficiency must be substantially improved compared with the Voyager engines.
If all the Voyager engines were removed then I'd have thought running them as push/pull with a modern loco would be similar fuel usage and efficiency to the TPE and Chiltern LHCS?

 

[fishwomp]

Problem is, that I don't think it would be very safe for the class 769 or 230s to try to be doing 125mph!

769 no problem - a 319 still has the record for third rail of something like 110mph..

As for the 230.. that would be lively.

 

[Bald Rick]

I think it's pretty clear that 5 intercity DMU engines would use more fuel than 1 big locomotive engine.

It’s Christmas time, and I‘ll be gentle, goodwill to all men and all that.

How much fuel is used is less a function of how many engines there are, or how big they are, but what work they are required to do. In this case, the work required is to accelerate a train from a stand to 100mph scores of times a day, counter the effects of rolling and air resistance for all the time it is moving, lift it from sea level to - cumulatively - several thousand metres above sea level each day, and provide ‘hotel’ power to all the services on the train.

I think it’s pretty clear that a train weighing 450-550 tonnes will require more effort to do this than a train weighing 280t, regardless of how many engines are employed to do it (within reason).


If it helps, look at it another way. Which would use more calories on an identical country walk with a few hills - you, or your slightly smaller friend giving you a piggyback?

 

[390136]

I’ve been told CrossCountry are removing all tilt mechanisms to save weight (they’ve always been disabled but still attached).

Attaching a loco to a DMU is just silly unless it’s for a rescue.

 

[Philip]

It’s Christmas time, and I‘ll be gentle, goodwill to all men and all that.

How much fuel is used is less a function of how many engines there are, or how big they are, but what work they are required to do. In this case, the work required is to accelerate a train from a stand to 100mph scores of times a day, counter the effects of rolling and air resistance for all the time it is moving, lift it from sea level to - cumulatively - several thousand metres above sea level each day, and provide ‘hotel’ power to all the services on the train.

I think it’s pretty clear that a train weighing 450-550 tonnes will require more effort to do this than a train weighing 280t, regardless of how many engines are employed to do it (within reason).


If it helps, look at it another way. Which would use more calories on an identical country walk with a few hills - you, or your slightly smaller friend giving you a piggyback?

Fair enough, points well explained. However I've still thought for a long time that having all engines running in Voyager sets especially is very inefficient and perhaps unnecessarily so. Could a 5-coach Voyager run on 3 engines and still keep to time, likewise a 220 with 2 engines running?

 

[Bald Rick]

Could a 5-coach Voyager run on 3 engines and still keep to time, likewise a 220 with 2 engines running?

No.

Multiple engines are only inefficient (compared to fewer, or one big engine) if they are not doing any work, ie idling. But by their nature, idling engines are not using much fuel.

 

[sprinterguy]

Hijacking the thread slightly, how does a 5 coach 221 compare with a tpe or Chiltern 68+5 set?

Generally accepted wisdom, supported by work around fuel useage I've done in the past, is that the Chiltern loco-hauled sets are at the break even point in terms of fuel use against a comparable length class 168 formation.

Similarly, using publicly available figures, Crosscountry's HSTs, with a pair of power cars, are about as fuel efficient as a comparable 8-car Voyager formation with their larger engines compared to a 168.

If one were looking for a loco-hauled solution to reduce Crosscountry fuel usage - given that a single diesel locomotive offers no advantage over the single Voyager set that many North East - South West services operate as - then I would have thought there'd be greater benefit to attaching a compatible push-pull capable electric loco to power services between Birmingham and Manchester, and York and Edinburgh/Glasgow: That's around 300 route miles where fuel usage and emissions at point of use could be reduced to zero, if this hypothetical loco were also able to provide train supply, representing over 8000 train miles a day even just based on an hourly service pattern as largely provided at present.

Not that such a suggestion is necessarily any more realistic or achievable, but one of the Voyagers' greater shortcomings over their full life cycle is their inability to use the overhead wires where they're available, and it'd also require a far smaller fleet of perhaps 12 locos, compared to having every long distance XC service diesel hauled throughout its journey for little appreciable benefit.

 

[yoyothehobo]

If all the Voyager engines were removed then I'd have thought running them as push/pull with a modern loco would be similar fuel usage and efficiency to the TPE and Chiltern LHCS?

This is quite possibly the most bizarre sentence i have read on the forum. And i remember the guy who wanted to reopen the Port Road.