ThePurplePrimer Posted February 8, 2015 Share Posted February 8, 2015 Hi Guys I was reading about gravity shunting a coach into a platform in the steam era ( East Kent Light Railway ) and it made me curious about the mechanics of that. I can see pictures of the locos which appear to have vacuum pipes so I assumed the coaches would have been vacuum fitted for brakes ? If that is the case then how would the brakes have been let off after the loco uncoupled to allow the coach(es) to run by gravity into the platform ( the passengers are still on board at this time ) - and then how would the brakes have been reapplied to stop it crashing into the buffers ( it is a single line terminus ) Link to post Share on other sites More sharing options...
Londontram Posted February 8, 2015 Share Posted February 8, 2015 On the Killin branch at Killin station on the old Callender and Oban line (Caledonian) the loco would uncouple from the coach leaving it in the platform and run down the grade past a set of points controlled by a ground frame then run back up into the goods yard. the Guard would then release the coach hand brake and the coach was allowed to free wheel under gravity past the siding stopping of its own accord a few hundred yards down the track. The loco would then come out the siding and couple up to the other end of the coach and pull it back into the platform. Not sure if this was done with passengers still on the coach though. I'm afraid other than releasing the hand brake I'm not sure how the braking was carried out Steve Link to post Share on other sites More sharing options...
LMS2968 Posted February 8, 2015 Share Posted February 8, 2015 The vacuum was normally in both the top and bottom chambers of the coach brake cylinder, in which case both sides were in equilibrium and the piston would fall by gravity to release the brakes. To apply the brakes, air was admitted to the bottom chamber, forcing the piston upwards to apply the brakes. However, if the was vacuum was destroyed in both top and bottom chambers, equilibrium is again present and the piston falls, releasing the brakes. There was a valve to each cylinder which was opened by 'pulling the strings' from ground level, allowing air into the top chamber again. This would release the brakes and allow the coaches to descend by gravity, under the control of the guard and his handbrake screw. When the loco was recoupled and vacuum recreated, the vacuum would enter both top and bottom chambers, restoring normality. The strings had also to be pulled if a GWR loco handed over to one from another railway, since the GWR worked on 25" of vacuum, the others 21". Unless this was done properly, the brakes would drag, much to the annoyance of those on the footplate! Link to post Share on other sites More sharing options...
ThePurplePrimer Posted February 8, 2015 Author Share Posted February 8, 2015 Thanks for the replies 'Pulling the strings' sounds interesting - could you expand on that please Link to post Share on other sites More sharing options...
AMJ Posted February 8, 2015 Share Posted February 8, 2015 Pulling the strings is easy to do. You need to ensure that the hand brake is on, and take a bag off (vacuum hose). The strings can be identified by the white star on the frames. On some vehicles you need to pull the string (a thin rope and wait for the piston in the cylinder to drop to the bottom. On others when you pull the string thepiston continues to drop after you have released the string. This is one of teh last tasks when disposing of stock at the end of each day. As an aside, the Manx electric does gravity shunts for the trailer cars. Link to post Share on other sites More sharing options...
Fat Controller Posted February 8, 2015 Share Posted February 8, 2015 Thanks for the replies 'Pulling the strings' sounds interesting - could you expand on that please Exactly as it sounds; there was a cord, or sometimes a wire loop, hanging down near the vacuum or air cylinder. If you pulled this, it would release the brake. Relatively straightforward on a static vehicle; the skill comes in when the vehicle is already moving, and you don't want it to stop yet. I've watched 'chasers' doing this at Lille Deliverance hump yard, when the brakes hadn't been fully released on a cut; they ran alongside the offending vehicles with a shunting pole, which they stuck through the loop at the end of the 'string'. This wasn't in the dim-distant past, but in the late 1990s, and the wagons were 80t bogie ones. Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted February 8, 2015 RMweb Gold Share Posted February 8, 2015 Pulling the strings is easy to do. You need to ensure that the hand brake is on, and take a bag off (vacuum hose). The strings can be identified by the white star on the frames. On some vehicles you need to pull the string (a thin rope and wait for the piston in the cylinder to drop to the bottom. On others when you pull the string thepiston continues to drop after you have released the string. This is one of teh last tasks when disposing of stock at the end of each day. As an aside, the Manx electric does gravity shunts for the trailer cars. Why release the brakes when disposing of stock? I can't quite see the point of that as the vacuum would gradually leak away in any case. We certainly never used to do it at a major passenger yard where I worked and in some cases it would save time when getting the stock ready for its next work as with luck there might be no need to completely blow-up the vacuum. Link to post Share on other sites More sharing options...
ThePurplePrimer Posted February 8, 2015 Author Share Posted February 8, 2015 Thanks Really interesting stuff Can I ask about the handbrake - would all coaches have a handbrake or just the ones designated 'brake' as in 'brake composite' for example Would they be a wheel you twiddled rather than a lever on a wagon ? Link to post Share on other sites More sharing options...
DavidB Posted February 8, 2015 Share Posted February 8, 2015 Pat Ransome-Wallis describes a round trip on the East Kent in his book On Railways at Home and Abroad (1951). The outbound train from Shepherd's Well was formed of an SECR O1, an ex-LSWR bogie brake composite and a brake van, while the return journey started with the same vehicles, plus 5 assorted vans and wagons, to which were added three more vans at Staple. The clear implication is that the whole train was loose-coupled - on arrival at Wingham on the outbound trip, "the engine came off the train and parked in a siding, while our guard took control of the train and we rolled gently down the bank into the station". On the return journey to Shepherd's Well "again we stopped short of the station while our engine came off and ran onto a siding. The coach, alone, followed and came to rest gently in the station. Back went the engine for the wagons and vans, which disappeared rapidly round the connecting line onto the Southern line. The brake van then came down to the station by gravity, the engine came home to the shed and within 5 minutes the East Kent had gone to sleep for the night". The whole chapter is a delightful read - recommended if you can get hold of a copy. David Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted February 8, 2015 RMweb Premium Share Posted February 8, 2015 The run round procedure at Yelverton for the Princetown branch coach, was for the train to arrive and having discharged the passengers was to propel the train back up the hill past the loco release siding. The loco then disconnected from the coach and proceeded into the siding, the coach then dropped down into the platform after the road had been reset. The guard controlling the speed with the handbrake. the engine then came down onto the coach for the next trip to Princetown. Link to post Share on other sites More sharing options...
Fat Controller Posted February 8, 2015 Share Posted February 8, 2015 Thanks Really interesting stuff Can I ask about the handbrake - would all coaches have a handbrake or just the ones designated 'brake' as in 'brake composite' for example Would they be a wheel you twiddled rather than a lever on a wagon ? Most passenger-carrying vehicles, apart from those designated 'Brake', had no form of parking brake. Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted February 8, 2015 RMweb Premium Share Posted February 8, 2015 Thanks Really interesting stuff Can I ask about the handbrake - would all coaches have a handbrake or just the ones designated 'brake' as in 'brake composite' for example Would they be a wheel you twiddled rather than a lever on a wagon ? Yes the brake wheel is in the guards brake compartment, the same arrangement as in a goods brake van. Link to post Share on other sites More sharing options...
RMweb Premium Reorte Posted February 8, 2015 RMweb Premium Share Posted February 8, 2015 Most passenger-carrying vehicles, apart from those designated 'Brake', had no form of parking brake. So that's why there was always a brake, so that the stock could stay put if the loco had to uncouple (e.g. for running round?) Is it also why you don't see them these days, because even when there is loco-hauled stock there's almost inevitably a cab at both ends, so never any need to remove the loco (or DVT?) On the other hand I don't recall anything that looked brake-like on the Sleeper. Link to post Share on other sites More sharing options...
Edwin_m Posted February 8, 2015 Share Posted February 8, 2015 Yes multiple units will have parking brakes controllable from each cab. Not sure which Sleeper you are referring to, but I believe the Great Western uses some Mk3 brake coaches which have very small guards/brake areas so look like normal coaches at first glance. Link to post Share on other sites More sharing options...
RMweb Gold TheSignalEngineer Posted February 8, 2015 RMweb Gold Share Posted February 8, 2015 Gravity shunting was a regular event in the South Bays at Rugby when the Peterborough line was open. After arrival the loco pushed the train back up the Peterborough line then went off to shed. The Guard then controlled the train back down into the platform. Link to post Share on other sites More sharing options...
APOLLO Posted February 8, 2015 Share Posted February 8, 2015 Gravity shonting was a regular event in the South Bays at Rugby when the Peterborough line was open. After arrival the loco pushed the train back up the Peterborough line then went off to shed. The Guard then controlled the train back down into the platform. Same thing happened at Manchester Victoria bay platforms. Loco would arrive, train unload then be pushed up Miles Platting bank a short distance, loco would then uncouple & run forward into a siding, guard would then roll the train slowly back into the bay platform. This is in the book "Manchester in the days of steam" by Paul Shackcloth, with photos of the operation as well (2-6-4 tank & suburban coaches). He mentions "pulling the string" to preserve the vacuum (keep brakes off) and hold / control the return with the handbrake. Of course he (the guard) could also destroy the vacuum to quickly stop the descent if things were not right. An extra safety feature of the move. Brit15 Link to post Share on other sites More sharing options...
45125 Posted February 8, 2015 Share Posted February 8, 2015 Same thing happened at Manchester Victoria bay platforms. Loco would arrive, train unload then be pushed up Miles Platting bank a short distance, loco would then uncouple & run forward into a siding, guard would then roll the train slowly back into the bay platform. This is in the book "Manchester in the days of steam" by Paul Shackcloth, with photos of the operation as well (2-6-4 tank & suburban coaches). He mentions "pulling the string" to preserve the vacuum (keep brakes off) and hold / control the return with the handbrake. Of course he (the guard) could also destroy the vacuum to quickly stop the descent if things were not right. An extra safety feature of the move. Brit15 If you have pulled the strings you have destroyed the vacuum. You only have the hand brake to control the movement. Link to post Share on other sites More sharing options...
Catkins Posted February 8, 2015 Share Posted February 8, 2015 Reorte - If you mean the Caledonian Sleeper, that runs between Scotland and London, then the brake vehicle is a rebuilt second open, with a guards compartment built into it at one end. This site - http://www.scot-rail.co.uk/page/Caledonian+sleepers - has a lot of information on it. Link to post Share on other sites More sharing options...
luckymucklebackit Posted February 8, 2015 Share Posted February 8, 2015 Gravity working was used at Buchanan St. See below "Loose Shunting of Empty Coaching Vehicles" Jim Link to post Share on other sites More sharing options...
AberdeenBill Posted February 8, 2015 Share Posted February 8, 2015 Gravity shunting was used at Bournemouth West but it all went horribly wrong on 17 August 1956. Apparently there was a non-corridor carriage in the rake and the guard couldn't reach the brake compartment to apply the handbrake... http://www.railwaysarchive.co.uk/eventsummary.php?eventID=6277 Bill Link to post Share on other sites More sharing options...
Boris Posted February 8, 2015 Share Posted February 8, 2015 Why release the brakes when disposing of stock? I can't quite see the point of that as the vacuum would gradually leak away in any case. We certainly never used to do it at a major passenger yard where I worked and in some cases it would save time when getting the stock ready for its next work as with luck there might be no need to completely blow-up the vacuum. Its a preservation era practice on some railways to prevent flattening of the rolling rings in the cylinders and therefore reduce faults and prolong the life of the ring. I believe its to do with the modern materials used in the manufacture by certain suppliers, but don't quote me on that. Link to post Share on other sites More sharing options...
roythebus Posted February 9, 2015 Share Posted February 9, 2015 I understand it was the practice at Cowes (Isle of Wight) for the loco to uncouple, run forward, then use the crossover to run round the stock. Having released the air brake using the string, the guard would then release his hand brake and let the stock run towards the stops, using the handbrake to stop the train. the loco in the meantime would have run round/watered/backed onto the train. Link to post Share on other sites More sharing options...
Swindon 123 Posted February 9, 2015 Share Posted February 9, 2015 Why release the brakes when disposing of stock? I can't quite see the point of that as the vacuum would gradually leak away in any case. We certainly never used to do it at a major passenger yard where I worked and in some cases it would save time when getting the stock ready for its next work as with luck there might be no need to completely blow-up the vacuum. Another reason for releasing the brakes on vacuum braked wagons, and I can't think why coaches would be any different, is that if you apply a handbrake on a vehicle that still has a bit of brake, air or vacuum, in it, when you come back to release the handbrake it is a hell of a lot harder than if you released the power brake and then applied the handbrake after. I was taught that when applying a handbrake on a vehicle always release the train brake on the vehicle before applying the handbrake. Lever brakes on a vacuum fitted wagon can take two of you to release them if it has been applied with the train brake still in it. One to stand on the brake stick and the other to pull the pin out. On air braked wagons, especially disc bogie braked vehicles it was not unknown for a handbrake applied without releasing the distributor to release itself as the air leaked off. Paul J. Link to post Share on other sites More sharing options...
Boris Posted February 9, 2015 Share Posted February 9, 2015 On wagon brakes that's correct because the brake cylinder put way more force into the brakes than you can with a brake stick and once the cylinder leaks off all that pressure goes back through the simple brake linkage to the pin on the brake rack. Coach handbrake systems work differently to wagons and applying the handbrake with power in the cylinder doesn't make much difference, although if you overtighten the handbrake it can be awkward to release. Conversely if you try and apply the handbrake with 21 inches of vacuum in the system the brake will not apply correctly, you need to zero it to get a full application on passenger stock. Link to post Share on other sites More sharing options...
edcayton Posted February 9, 2015 Share Posted February 9, 2015 Wellington (Salop) used this practice. There is a model of it on the circuit, with authentic "gravity" working. Ed Link to post Share on other sites More sharing options...
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