Slip coaches

Not heritage as such, but...
How did slip coaches work? How did they uncouple, and the brake hose too? How do do you pick them up again on the way back?

 

The picking up bit was relatively simple - you stopped and attached them in the normal way. So a slip service was essentially unbalanced: a carriage could be slipped in one direction without the main part of the train needing to stop, but the balancing working on the return had to stop.

Tom

 

Yes, the brakes were sealed off before the coach was disconnected. The slip coach guard then used brakes to bring it to a stand at the station and then later it was shunted away. Not efficient as you need a second guard for the slip coach (the first one stays in the continuing train) and another engine and crew to retrieve the empty slip carriage afterwards. Also, slipping breaks one of the rules of signalling in that you effectively have two trains moving in the same block simultaneously and there were a few accidents where a slip coach ran into the back of the main train which had slowed down.

See http://www.railwaywondersoftheworld.com/slip-coaches.html from 1935 for more.

BTW, I seem to remember reading somewhere that experiments were done on attaching coaches to moving trains - reverse slipping if you like - though it sounds like a recipe for disaster. This was sometime in the Victorian period in France but I can't recall any more - sorry.

 

I believe the L.N.W.R. had at least one corridor equipped slip coach so its passengers could avail themselves of the dining car early in the journey. Inevitably some tarried in the dining car and did not get back in time!

PH

 

Yes an inferior railway would get it wrong, as the GWR had slip coaches with corridor connection at one end such as F14, so a three coach slip including the slip coach, dining car and and brake third, could be done such at Taunton at one time and the slip section was taken onto Ilfracombe

 

This page has a description of the operation of a slip from the guards point of view, and some good photos of the coupling hoock, leaning towards GWR practice:

http://www.railwaywondersoftheworld.com/slip-coaches.html

Tom

 

Oh dear! More tribalism.

PH

 

Video clip of a Slip vehicle under test behind a 37 on the GCR recently.
The 37 had to run at 60 plus for a while after slipping.

 

What was the point of this test?

 

Not *every* instance of someone saying one practise on one railway is better than on another is tribalism! In this case it seems quite sensible, solving a problem you yourself raised surely?

Sent from my Moto G (4) using Tapatalk

 

The first eight words are tribalistic in tone.No problem with the tenth word onwards which are purely factual.

PH

 

Railway Roundabout clip of the last slip at Bicester in 1960:—

 

Possibly related to this from "A History of Slipping and Slip Carriages" by CEJ Fryer. The Times on 30 November 1858 reported on a proposal by French engineer M. Guichard Petrus for the use of special machinery at the lineside to lift and replace the body of the last coach on a train from its frame while in transit. Herpath's Railway and Commercial Journal of 11 December 1858 referred to the proposal and concluded "If an experiment of this kind should ever be attempted, we hope the inventor will not fail to be one of the party to be caught up, but before he do so, let him make his will and take leave of his friends."

Fryer comments that Petrus' proposal may have been tongue in cheek rather than serious. If the latter, it was not made clear whether the equipment would be stationary (which would deliver a tremendous g-shock to the passengers) or would run on a lengthy parallel line. Either way, as Fryer notes, it seems analogous to using a steam hammer to crack a nut.

 

Thanks everyone, very interesting.

 

Looking at a map of GWR territory, one can see why slip coaches were a useful option: the whole network extended out into less and less populated areas, with the few larger towns only part-way along the main lines.
Comparing to e.g. the LNWR, which had either large cities (Liverpool, Leeds, Manchester) or important onward connections (Carlisle, Holyhead) at the far end of all the main lines, meaning heavy traffic right to the far end of the run.
On the GWR, a heavily loaded train leaving Paddington must have been half empty after the first hundred miles or so. On the LNW (or Midland, or GN/NE) they must have been still pretty full the whole distance.

 

I am intrigued by having a slip corridor connectionThe standard gangway is a floppy beast. In stowed position there are hooks each side to hold the bellows closed. In the joined position there are clips which hold the two bellows ends together. If clipped together how were the clips released. They are a two handed job with the coaches stationery and balancing on both buffer casings

 

I have seen a photograph but I cannot recall where. Perhaps someone else can.

PH

 

i think the clue is in the words "at one end" ie not the slip end...

 

The coaches on the GWR at least seemed to have had a droplight window in the slip end of the coach. The slip hook also I believe had two hooks. One for when it was in normal use. At the last stop before the slip the guard would move the coupling into the moveable part of the drawhook. Before the slip he would open the droplight window and this allowed him to reach out and undo the vacuum brake hose. Then when he was ready to release he moved a lever inside and it allowed the hook to open up and the coupling parted company.

I think at least some (if not all) of the coaches had vacuum tanks which could maintain the vacuum for a period after it had been disconnected. I have seen a least one picture of a clerestory slip coach and the tanks were on the roof either side of the clerestory. Of course they also had a handbrake. Some trains seem to have had several slip coaches and would slip them off at different locations.

 

According to CEJ Freyer, the LNWR 'corridor slips' which allowed passengers to access the restaurant car from the slip portion were introduced in early 1914 but discontinued at the outbreak of WW1. He states 'No resumption was made after 1918, nor did any other line adopt the practice, so far as is certainly known'.

The 'corridor slip' process gets only a brief description, namely that the slip guard sealed off the gangway connection from within his compartment using a 'sealing off mechanism' before making the slip . Unfortunately the book has no photo or further information how this worked.