Slip coaches & Slipping Distant signals

[Springs Branch]

I was reading recently about the operation of slip coaches.

One thing mentioned was that on the approach to the station where a slip coach would be detached, there was a Slipping Distant semaphore signal.

The purpose of the Slipping Distant was to inform the driver (and presumably the slip coach guard) whether it was safe to drop the slip coach as planned, or that "something was up" and the whole train had to make a conventional stop at the platform.

Does anyone know what form the Slipping Distant had?

I know that slip coaches were a particular favourite of the Great Western, and the GWR sometimes adorned their semaphore arms with things like an "O" or an "S". Was there a special designation for a Slipping Distant, and could this signal be ignored by drivers of all other trains?

 

[O L Leigh]

I found this webpage which has a drawing and explanation of slipping distants.

 

[edwin_m]

I found this webpage which has a drawing and explanation of slipping distants.

Just a general note for people reading that - it confuses home signal with stop signal. This doesn't affect the description of the slipping distant.

 

[Ken H]

I found this webpage which has a drawing and explanation of slipping distants.

good link. ta

 

[Taunton]

A common reason for not slipping was fog, where the slip guard might not keep the main train adequately in sight. Always a particular concern was at the slipping detachment the self-seal vacuum on the main train might not work, the brakes would come on hard, and the slip coach run into it. The procedures were very precise on how to avoid this, basically by the slip guard paying close attention ahead, but also the train loco had to keep steam on to pull clear.

At Taunton, a slipping point, I don't recall a special signal, but all had to pay attention to the Taunton East Down distant; if it was on, no slipping, the train was to stop. This might be what was referred to. There were all sorts of special bell codes between adjacent boxes when slipping was in progress.

The slip coach was given up by my time, but my grandfather was apparently a periodic patron, as described here :

"...and our fathers that begat us..." | RailUK Forums (railforums.co.uk)

 

[Ashley Hill]

Here's a photo from gwr.org showing Reading's slipping distants taken by Adrian Vaughan plus a link to the site.

The Slip Coach

GWR slip coach

www.gwr.org.uk

 

[Springs Branch]

I found this webpage which has a drawing and explanation of slipping distants.

Here's a photo from gwr.org showing Reading's slipping distants taken by Adrian Vaughan plus a link to the site.
View attachment 106469

Thanks for the links. They pretty much answer my question on the special arms and their relationship to the normal running signals.

A common reason for not slipping was fog, where the slip guard might not keep the main train adequately in sight. Always a particular concern was at the slipping detachment the self-seal vacuum on the main train might not work, the brakes would come on hard, and the slip coach run into it. The procedures were very precise on how to avoid this, basically by the slip guard paying close attention ahead, but also the train loco had to keep steam on to pull clear.

That's interesting - I was wondering whether there were any "Fog and Falling Snow" rules restricting slip coach operations. Presumably slipping coaches was only ever contemplated during the hours of daylight too.

Although it always sounded like a bit of a hare-brained wheeze dropping coaches full of passengers off the back of moving expresses and letting them trundle into the station under their own momentum, I suppose whenever a bit of slipping was due to be done, there was careful scrutiny from many pairs of eyes - from ultra-close attention by the signalmen, to the gold-braid-capped supervisor on the platform. No doubt the job of Slip Guard was only ever assigned to a steady, experienced man with many years on the Railway, plus the station pilot loco would be standing by in case the portion undershot or overshot its stopping point and needed a prompt re-positioning.

IIRC, one of the most white-knuckle slip coach operations was by the L&YR's Manchester - Colne expresses, which ran via the Bury & Ramsbottom route and dropped a slip coach at Accrington, right at the bottom of the steep 1-in-40 Baxenden Bank, just where the track had a very sharp curve through the (now closed) platforms at Accrington station.

 

[Gloster]

There are two accident reports on the Railways Archive site that may be of interest (sorry, I can’t do a link): Marks Tey 29 December 1906 and Woodford & Hinton 19 December 1935.

 

[edwin_m]

There are two accident reports on the Railways Archive site that may be of interest (sorry, I can’t do a link): Marks Tey 29 December 1906 and Woodford & Hinton 19 December 1935.

Accident at Marks Tey on 29th December 1906 :: The Railways Archive
Accident at Woodford & Hinton on 19th December 1935 :: The Railways Archive

 

[Taunton]

Here's a photo from gwr.org showing Reading's slipping distants taken by Adrian Vaughan plus a link to the site.

The Slip Coach

GWR slip coach

www.gwr.org.uk

View attachment 106469

Were those signals pulled off for every service, or only for one which was slipping? If the former they are really just splitting distants, which were not common on the GWR but there were a few. If the latter, must have been a bit confusing to normal services with a clear run.

 

[O L Leigh]

Were those signals pulled off for every service, or only for one which was slipping? If the former they are really just splitting distants, which were not common on the GWR but there were a few. If the latter, must have been a bit confusing to normal services with a clear run.

I would imagine that, like the stupid double-headed signals that persist at Tilehurst, traincrew got used to them pretty quickly and would know what each indication meant.

 

[Taunton]

Slip coaches were an operational nuisance for how to get them back to base, being obviously a one-way only service. The first GWR slip from the Cornish Riviera at Westbury was ingenious, detached there and, after the 1930s avoiding line was built, needing the Westbury pilot to go out to Heywood Road Junction to take it in to the station and then, with several manoeuvres, adding it to a Weymouth service to provide a through service to Castle Cary, Yeovil, etc. From Weymouth it was hauled backwards in the evening on a Bristol service, then the next day it was added to a Paddington service, now being the right way round, to be slipped at Reading. Taken on by a local service, it could restart the cycle, for which two vehicles were required.

 

[AndrewE]

Some years ago I flagged up this video

I don't know whether it shows the signalling. It does show that the points don't get moved to bring the slipped coach into the platform - here at least - (which is what I used to imagine happened) but the station pilot or train engine which works it forward goes to collect it off the line on whichthe express went through.

 

[30907]

Thanks for the links. They pretty much answer my question on the special arms and their relationship to the normal running signals.


That's interesting - I was wondering whether there were any "Fog and Falling Snow" rules restricting slip coach operations. Presumably slipping coaches was only ever contemplated during the hours of daylight too.

ISTR there was a fog/snow rule - but not a daylight one: the 5.10pm Paddington-Bicester slip, the last to survive, would have arrived in darkness at this time of year.

From Weymouth it was hauled backwards in the evening on a Bristol service, then the next day it was added to a Paddington service, now being the right way round, to be slipped at Reading. Taken on by a local service, it could restart the cycle, for which two vehicles were required.

Not occurred to me before, but did it need to go round the Greenford loop to face the correct way for a Down train?

 

[Taunton]

Not occurred to me before, but did it need to go round the Greenford loop to face the correct way for a Down train?

I think the turntable at Old Oak Common was used.

 

[30907]

I think the turntable at Old Oak Common was used.

Forgot that option, obvious really.

 

[Ashley Hill]

Were those signals pulled off for every service, or only for one which was slipping? If the former they are really just splitting distants, which were not common on the GWR but there were a few. If the latter, must have been a bit confusing to normal services with a clear run.

If they had been considered as normal distant signals for the next box ahead they would have been positioned under the main arm to which they applied.
Both slip distants shown are motor worked and interlocking (or perhaps slotting on others) would prevent them being pulled unless the main arm was off and the route proved clear and through the station. The actual distant proper being off would prove this of course so presumably the slipping distant being off too confirmed it was safe to slip.

 

[edwin_m]

The 1906 accident I linked above demonstrates how using a normal distant as an indication of whether to slip could be dangerous, although the slip guard was held primarily responsible. Due to fog it was decided to stop the train rather than attempt slipping, but too late to inform the driver at the previous station so the signals were kept at danger to stop the train in the station. The driver saw the distant at caution, decided to run through the home signal because of the risk that the slip had taken place, by that logic should have run right through the platform as well but didn't. The slip guard missed the distant but assumed due to the lack of braking that the train wasn't stopping so it would be OK to slip.

 

[Rescars]

Just speculating, but were whistle codes ever used from the loco to advise the slip guard about whether or not the driver intended to stop or keep going?

 

[Gloster]

Just speculating, but were whistle codes ever used from the loco to advise the slip guard about whether or not the driver intended to stop or keep going?

I doubt it. With the general noise of travelling, you couldn’t be certain that the slip-guard would hear and correctly understand the whistle code. And he had no way of replying to it to confirm that he had heard it.

 

[Graham H]

This may need to be a separate thread or even answered before but I often wondered about portion v slip working as to which gave the passenger a better service. Consider the GWR and SR who both had prime services to the West Country. The Southern ACE had portions so by default had to stop to drop off coaches. The GWR Cornish Riviera used slip coaches so no need to stop the main train.
My main areas of thought would be
1. The ACE provided both down and up service but at the cost of down stops and a very complex reform of portions on the up service.
2. By contrast the down GWR service would appear better for each destination as it had fewer stops BUT there is no reciprocal up service. The main train would of course return from the West Country but would presumably be just a short formation. Other than in summer when slip portions became extra through trains did passengers who had the speed and convenience of a slip coach and facilities of the express on the way down just have to take any convenient up service ?
3. Although the ACE had a complex process of reforming the various portions (mainly at Exeter) it was at least still a prestigious service both ways.
4. Logistically how did all those GWR slip portions get back to London ? Presumably attached to convenient up trains but were these empty coach workings or did they provide passenger accommodation albeit in the ordinary, non express, sense.

 

[AndrewE]

I doubt it. With the general noise of travelling, you couldn’t be certain that the slip-guard would hear and correctly understand the whistle code. And he had no way of replying to it to confirm that he had heard it.

GWR locos had separate "Brake" whistles (presumably for communicating with guards at the back of unfitted goods trains,) so they must have been used at some time. Whether guards in a slip coach at passenger speeds could have heard a whistle signal I don't know.

When you see the expertise (route knowledge) of Post Office staff in "Night Mail" and understand that goods guards had to use the handbrake to keep unfitted trains in tension regardless of uphill and downhill variations on some routes, then I wouldn't be surprised if they could pick up a whistled signal. That video shows a dropped window in the front of the slip coach, presumably it might have been opened to hear a whistle?

 

[Gloster]

Reading up on this, although I had started on another subject, there are no references to the loco using its whistle. I think the slip-guard had only his route knowledge as to where to watch for the Distant to check the train was going to run through. The guard of the main train would be watching from his van and as soon as he saw that the slip had taken place, would indicate this (probably by a green flag or light) to the driver, who would presumably be looking back along the train.

One other thing I found was that there were also mail slip carriages. One, probably containing mail off trans-Atlantic steamers for Wales or the Midlands and beyond, was slipped at Pylle Hill in Bristol early in the last century.

 

[Taunton]

I believe that if slipping was not to take place the signalbox before the slipping point was advised and had to keep their distant at caution. This was a GWR thing, they would do the same for permanent way slacks when other companies just relied on boards.

The driver seeing this would make an immediate full brake application, destroying the vacuum and this registering on the vacuum gauge by the slip guard, who was watching the gauge closely at this point. This was how they signalled they were going to stop. Slipping was not allowed if the vacuum was not fully charged. The driver would blow the brake off again. The same would apply if the signalbox, for some reason, could not give a clear run.

Looking back from the footplate to see the slip had happened was for the fireman. The driver stayed very much looking ahead. I believe also when the slip happened there would be a momentary murmur in the vacuum gauge as the self-sealing valve operated, which the driver was looking for. If the valves failed and the vacuum dropped off, then it was full regulator and full ejector to try and keep ahead of the slip with the brakes dragging, and stop at the signal beyond the platform.

 

[AndrewE]

One other thing I found was that there were also mail slip carriages. One, probably containing mail off trans-Atlantic steamers for Wales or the Midlands and beyond, was slipped at Pylle Hill in Bristol early in the last century.

That's interesting: a slip coach off an up train. Most unusual, although the reason is obvious, it's one of the few time-critical traffics originating far away from London.

 

[30907]

This may need to be a separate thread or even answered before but I often wondered about portion v slip working as to which gave the passenger a better service. Consider the GWR and SR who both had prime services to the West Country. The Southern ACE had portions so by default had to stop to drop off coaches. The GWR Cornish Riviera used slip coaches so no need to stop the main train.
My main areas of thought would be
1. The ACE provided both down and up service but at the cost of down stops and a very complex reform of portions on the up service.

One stop both ways (Sidmouth Jn), and a slightly extended stop at Exeter to slot the restaurant cars in the middle.

2. By contrast the down GWR service would appear better for each destination as it had fewer stops BUT there is no reciprocal up service. The main train would of course return from the West Country but would presumably be just a short formation.

Not significantly shorter, at most 3 vehicles IIRC (and only 1 post WW2).

Other than in summer when slip portions became extra through trains did passengers who had the speed and convenience of a slip coach and facilities of the express on the way down just have to take any convenient up service ?

They couldn't access the restaurant car

3. Although the ACE had a complex process of reforming the various portions (mainly at Exeter) it was at least still a prestigious service both ways.
4. Logistically how did all those GWR slip portions get back to London ? Presumably attached to convenient up trains but were these empty coach workings or did they provide passenger accommodation albeit in the ordinary, non express, sense.

It varied, and there were slips at Reading in the up direction, see #6

 

[Western 52]

Were slips only ever single coaches, or were slip portions of multiple vehicles ever tried?

 

[AndrewE]

Were slips only ever single coaches, or were slip portions of multiple vehicles ever tried?

The article linked in post #6 says that portions several coaches long were slipped.

Each slip coach could have up to four 8-wheeled coaches behind it – or six 4 or 6-wheeled coaches – but that many was very unusual.In the 1910 timetable there were a couple of trains booked to have three behind but usually it was only one.

Above that they ran several portions as independent trains. It also says that 3 up trains slipped portions at Reading, the 8.30 Plymouth and the 8.20 Weston-super-Mare and the 8.30 Weston. Maybe like the up WCML trains used to stop at Watford Jn to set down for the N suburbs.

 

[Gloster]

Were slips only ever single coaches, or were slip portions of multiple vehicles ever tried?

I believe that the very last slip was of three coaches: a GWR slip, a LNER SK and a BR CK. I think that this was not uncommon with this train on Fridays, although the GWR apparently allowed three vehicles behind the slip coach. (Many of the shots in the Railway Roundabout film would have been taken on other days.)

 

[Rescars]

Although slipping is forever linked with the GWR main line, I believe it was a more widespread practice in earlier years. IIRC there was at one time a slip working to enable passengers from Ireland to reach Aberystwyth. Do others have favourite examples of improbable slip coach destinations?