Diesel tailing idling

[mp01]

Saw 45212 at Cardiff yesterday on the Cathedrals express and noticed that the 47 on the back was idling and wondered why - does this assist in any way, or just provide ETS or what? And is this what normally happens on railtours? Just curious...

 

[trainmania100]

It's a backup if the loco struggles or fails.

 

[The_Engineer]

It avoids having to run round the leading locomotive at destination, or other changes of direction.

 

[mp01]

Thanks - I can see that my question was ambiguous! Those are both reasons for the loco being on the back, and in fact this one did turn round east of Newport. But my question was why was the loco idling rather than switched off.

 

[The_Engineer]

Thanks - I can see that my question was ambiguous! Those are both reasons for the loco being on the back, and in fact this one did turn round east of Newport. But my question was why was the loco idling rather than switched off.

As the leading locomotive was a steam locomotive, if the Class 47 on the rear was ETS fitted it would have been providing the supply for the train. Unless (of course) if there was a generator van in the train doing that job, in which case the Class 47 was left idling to be ready for the turn around you mentioned.

 

[Cowley]

Last Sunday’s tour with 45212 down to Kingswear had a 37 at the rear in both directions which sounded like it was assisting (at least more than taking its own weight).
I wondered if there was some concern about fire risk as it’s been very dry down here?

 

[Sean Emmett]

I saw the Cardiff trip at Newport, with 'Braunton' masquerading as 'Lord Downing'. The Saphos rake has Mk2 air cons, not really suitable for steam specials, which need an ETH supply. Saphos say they take a diesel for insurance against failure but it doesn't assist. However, there is some debate about that on the National Preservation website

The RTC and SD Dartmouth trips with 45212 both had diesels for assistance on the Torbay & Dartmouth with its 1:60 gradients. There was some discussion about this too on Nat Pres, esp when steam loco slipped at Greenway tunnel but diesel kept shoving, leading to emergency stop so the steam loco crew could regain control of the train.

On Sun 17 Jun Clan Line ran Bristol - Par and return with load 10 unassisted, so no fire risk. But that may change with hot weather forecast next week. My logs of that run are on Nat Pres if anyone's interested.

 

[221129]

Last Sunday’s tour with 45212 down to Kingswear had a 37 at the rear in both directions which sounded like it was assisting (at least more than taking its own weight).
I wondered if there was some concern about fire risk as it’s been very dry down here?

I believe there was some riot with the Kettle at Taunton which lead to the 37 going on the back and giving it a shove.

 

[KingDaveRa]

I recall reading some time ago that a condition of running steam on mainlines (and probably any preserved locos) is there must be a second loco in the train as a contingency. Is that correct? Given the fact a great deal of the rail network is set up for push-pull nowadays anyway, it'd make sense for that reason alone. When I saw Flying Scotsman go through the Chilterns last year I think there was a 37 on the back of it burbling away.

 

[221129]

I recall reading some time ago that a condition of running steam on mainlines (and probably any preserved locos) is there must be a second loco in the train as a contingency. Is that correct? Given the fact a great deal of the rail network is set up for push-pull nowadays anyway, it'd make sense for that reason alone. When I saw Flying Scotsman go through the Chilterns last year I think there was a 37 on the back of it burbling away.

In a word, no this is not correct.

 

[KingDaveRa]

In a word, no this is not correct.

Fair enough. Can't remember where I read it now, but it sounded reasonable at the time.

 

[Cowley]

Fair enough. Can't remember where I read it now, but it sounded reasonable at the time.

You’re not the first person to mention this KingDave.
There’s actually plenty of steam specials that do run without a diesel in the consist, but usually they’re used for shunt releases etc.
Certainly useful to have a diesel on the back when things do go wrong though...

 

[43096]

You’re not the first person to mention this KingDave.
There’s actually plenty of steam specials that do run without a diesel in the consist, but usually they’re used for shunt releases etc.
Certainly useful to have a diesel on the back when things do go wrong though...

Especially if the train is from the 19th century and still has vacuum brakes..... Vac brake locos are not exactly plentiful!

 

[tiptoptaff]

Especially if the train is from the 19th century and still has vacuum brakes..... Vac brake locos are not exactly plentiful!

All current heritage stock certified for mainline running is 20th century

 

[43096]

All current stock certified for mainline running is 20th century

Actually, quite a bit is 21st Century....

 

[tiptoptaff]

Actually, quite a bit is 21st Century....

Duly edited

 

[341o2]

It avoids having to run round the leading locomotive at destination, or other changes of direction.

Usual procedure with steam charters London to Weymouth, where the diesel at the rear pulls the train back to Southampton where it reverses

 

[AndyY1951]

Going back to the original question which hasn't really been addressed, is one of the reasons for the diesel locomotive idling is that a lot of older big engines can't be turned on and off willy-nilly like a motor car. They have to be pre-heated and lubricating oil circulated around the engine before starting to minimise wear, so it makes sense to leave the engine running so it can be available quickly when needed.

 

[EE Andy b1]

Going back to the original question which hasn't really been addressed, is one of the reasons for the diesel locomotive idling is that a lot of older big engines can't be turned on and off willy-nilly like a motor car. They have to be pre-heated and lubricating oil circulated around the engine before starting to minimise wear, so it makes sense to leave the engine running so it can be available quickly when needed.

Most of the above probably cover the reasons, as long as the loco is manned whilst running for fire precautions, although class 66s don't catch fire.

Turning on and off a diesel engine willy-nilly does not do it any good. Doesn't help the batteries much either.
As you say when staring the engine it will go through a priming process that doesn't usually take too long, 30s to a minute maybe, will turn and then fire, hopefully.
The longest wait normally is the build up of main air on the locomotive.
If the loco is being dragged dead it would need to have equipment isolated, drivers safety device, battery and so on, which would all take time.
So if the loco is manned and running and communication with the lead loco, can assist if and when required especially if running late.

But the big thing at the moment as already mentioned is fire risk from sparks/cinders off steam locomotives under load so the diesel can take most of the strain but then normally that diesel would be inside the steam loco.