Instanter Three-Link Coupling

[rocor]

I was looking at a image of a Instanter type three-link coupling, and was intrigued by a couple of features.

 

1) The two small horns hanging down from the central link.

 

2) the twist in one of the end links.

 

I would be grateful if anyone could let me know what are the functions these items perform. 

 

Ron

 

 

 

[Trog]

I think the hooks on the centre link may be so the shunter can get a grip on it with the hook on the end of his pole, to turn it to and from the close and loose coupled directions. The pinch in the right hand link drops through a slot towards the back of a wagons gedge hook, then once the link is rotated so the hook is at the end of the link the fatter round section of the link is too big to come back out through that slot and the coupling is held captive so preventing it falling off the wagon when it is the spare and the wagon bounces.

Edited August 16, 2017 by Trog

[rocor]

I think the hooks on the centre link may be so the shunter can get a grip on it with the hook on the end of his pole, to turn it to and from the close and loose coupled directions. The pinch in the right hand link drops through a slot towards the back of a wagons gedge hook, then once the link is rotated so the hook is at the end of the link the fatter round section of the link is too big to come back out through that slot and the coupling is held captive so preventing it falling off the wagon when it is the spare and the wagon bounces.

Many thanks for the rapid reply to my query.

[jim.snowdon]

I think the hooks on the centre link may be so the shunter can get a grip on it with the hook on the end of his pole, to turn it to and from the close and loose coupled directions. The pinch in the right hand link drops through a slot towards the back of a wagons gedge hook, then once the link is rotated so the hook is at the end of the link the fatter round section of the link is too big to come back out through that slot and the coupling is held captive so preventing it falling off the wagon when it is the spare and the wagon bounces.

Correct, and the hooks on the Instanter link were an addition compared to the original GWR design, so were presumably incorporated as a result of feedback from the shunters. That they could be provided at all is a consequence of the change in the way these links were manufactured, the GWR design being forged from round bar in the same way as any other chain link. I am not of the manufacturing process for the BR version of the link was made - drop forging would seem to be the obvious approach, but for that, a basic link still has to be fashioned, potentially by the same process as for the normal links.

 

The reason behind the Gedge hook (and link) is that it allows the drawhook and the coupling links to be treated as separate items in respect of testing, inspection and repair. It probably also reduced the manufacturing cost, as to prior to their adoption, the top link of the coupling had to be threaded through the drawhook before being welded shut, after which the whole coupling assembly would have been a rather heavy and unmanageable object. Travelling wagon repairers probably had a few things to say about that whenever a drawhook or coupling got broken in service.

 

Jim

[The Johnster]

A word about these couplings in operation; they could be deployed in a 'long' or 'short' configuration a and the diagram shows a coupling in the short configuration.  The 'long' or 'loose coupled' position was used for 25 mph mineral  and unfitted traffic, class H or K trains and class 9 in later days, and the 'short' or 'tight coupled' for express freight of classes C, D, E, or F at originally up to 60mph, but later reduced to 45mph if there were any wagons with wheelbases of 10' or less, which means class 6, 7, or 8 in diesel times.  Couplings were often changed from the short to the long position using the horns in order to facilitate shunting.

 

They were very easy to use and reliable in service, and in 8 years as a guard at Canton in the 1970s I never heard of a breakage involving one; axle failures were more common.

[brossard]

This is very interesting.  I learned several things today.  Thanks.

 

John

[LMS2968]

They were a good idea and a close coupled pair of wagons could be unhooked entirely from outside with the pole, first by using the hooks to move the centre link into the long position, then the lifting the end link off in the normal way. Two wagons could also be coupled in the long position from outside, but I never found a way of moving the link to the short position without going underneath.

[The Bigbee Line]

They were a good idea and a close coupled pair of wagons could be unhooked entirely from outside with the pole, first by using the hooks to move the centre link into the long position, then the lifting the end link off in the normal way. Two wagons could also be coupled in the long position from outside, but I never found a way of moving the link to the short position without going underneath.

When I was a Movements Inspector, one of my guys Donald 'Dave' Davidson, an ex Dover Ferry shunter, demonstrated coupling and screwing up a Screw Coupling with a pole.  He could also 'flick' an instanter into the short position with his pole.  Very talented man.  He also related that some shunts onto the Eastern Docks were 'double coupled', both three link couplings were put up, twisted round each other.  I would like to have seen that.

[The Bigbee Line]

A word about these couplings in operation; they could be deployed in a 'long' or 'short' configuration a and the diagram shows a coupling in the short configuration.  The 'long' or 'loose coupled' position was used for 25 mph mineral  and unfitted traffic, class H or K trains and class 9 in later days, and the 'short' or 'tight coupled' for express freight of classes C, D, E, or F at originally up to 60mph, but later reduced to 45mph if there were any wagons with wheelbases of 10' or less, which means class 6, 7, or 8 in diesel times.  Couplings were often changed from the short to the long position using the horns in order to facilitate shunting.

 

They were very easy to use and reliable in service, and in 8 years as a guard at Canton in the 1970s I never heard of a breakage involving one; axle failures were more common.

The cast centre links were tested by MPI as they tended to develop hair line cracks.  Any P4 modeller of MGR wagons should add a little white to this part of the coupling to represent the white contrast paint used in that process. 

[LMS2968]

When I was a Movements Inspector, one of my guys Donald 'Dave' Davidson, an ex Dover Ferry shunter, demonstrated coupling and screwing up a Screw Coupling with a pole.  He could also 'flick' an instanter into the short position with his pole.  Very talented man.  He also related that some shunts onto the Eastern Docks were 'double coupled', both three link couplings were put up, twisted round each other.  I would like to have seen that.

A talented man indeed. But as to twisting the three links, I'd bet he wasn't popular when the train reached its destination!

[The Bigbee Line]

A talented man indeed. But as to twisting the three links, I'd bet he wasn't popular when the train reached its destination!

Only for shunts onto the piers, not for the main line.

[Poor Old Bruce]

Correct, and the hooks on the Instanter link were an addition compared to the original GWR design, so were presumably incorporated as a result of feedback from the shunters. That they could be provided at all is a consequence of the change in the way these links were manufactured, the GWR design being forged from round bar in the same way as any other chain link. I am not of the manufacturing process for the BR version of the link was made - drop forging would seem to be the obvious approach, but for that, a basic link still has to be fashioned, potentially by the same process as for the normal links.

 

The cast centre links were tested by MPI as they tended to develop hair line cracks.  Any P4 modeller of MGR wagons should add a little white to this part of the coupling to represent the white contrast paint used in that process. 

 

The Instanter links were, indeed, drop forged (not cast Ernie) from a plain billet of steel and then the flash punched off. At Derby, samples of all batches of Instanters used to be proof tested by the Materials Inspection Bureau in the Loco Works opposite the top end of Platform 6. They were tensile tested to a proof load (IIRC 80 Tons) and checked for distortion, then tested to failure. If the sample failed the test, the batch was then given more heat treatment and re-tested.

[The Bigbee Line]

The Instanter links were, indeed, drop forged (not cast Ernie) from a plain billet of steel and then the flash punched off. At Derby, samples of all batches of Instanters used to be proof tested by the Materials Inspection Bureau in the Loco Works opposite the top end of Platform 6. They were tensile tested to a proof load (IIRC 80 Tons) and checked for distortion, then tested to failure. If the sample failed the test, the batch was then given more heat treatment and re-tested.

Richard,

 

Thanks for the correction, not sure why I said cast....  I've seen the 'things' that were used to make the forgings at Unilathe in Stoke.  I can't remember why I was there, but the had the tooling to make all sorts of railway items. 

 

Best regards,

 

Ernie

Edited August 17, 2017 by The Bigbee Line

[The Johnster]

They were a good idea and a close coupled pair of wagons could be unhooked entirely from outside with the pole, first by using the hooks to move the centre link into the long position, then the lifting the end link off in the normal way. Two wagons could also be coupled in the long position from outside, but I never found a way of moving the link to the short position without going underneath.

 

You could 'shorten' the couplings using the hooks, but the train had to be buffered up, with all buffers compressed and the couplings as slack as possible.  This was often not practical (if the loco was not present and you had nothing to squeeze the train against if it was, for example) and it was usually easier to go between.  This of course had it's own risks, especially if nobody knew you were there; we used to leave the shunting pole propped against the wagon as an indictation.  I have seen screw couplings coupled and tightened with shunting poles from outside, but was never able to do it myself.

 

When I first started on the railway at Canton in the 70s, I had a 5 week wait for the next guard's school course to start, which I spent learning what ropes I could at Penarth Curve North goods yard, between the shed and the old Ninian Park football ground next to Ninian Park Halt, all housing now.  This was a great place to pick up skills, with trip workings to Ferry Road and Ely Paper Mill, and a good bit of 'ballast' work making up trains for weekend jobs as well.  George Colwall, the head shunter, would take me down a train of wagons with a pole and, having taught me to uncouple with it, then took me back up the train coupling up, and then back down again seeing how many instanters I could get into the short positing without going between, then lengthening them again.  I became able to use a pole reasonably well, but to be honest never really mastered the art, and would be useless now!

[sir douglas]

a hook and instanter chain in the bushes at Oakenshaw foot crossing

[The Johnster]

This photo shows the 'pinch' and 'gedge' hook very clearly.  The spare emergence screw couplings carried in passenger brake vans also had this feature.

[Titan]

This photo shows the 'pinch' and 'gedge' hook very clearly.  The spare emergence screw couplings carried in passenger brake vans also had this feature.

 

Are you sure? I thought the emergency couplings specifically did not have this feature so that they could not be used to replace a normal coupling. This would be important since the emergency couplings would be shorter as they would go hook to hook, which is a shorter distance than a normal coupling that would go hook to hole.

[The Bigbee Line]

Some diagrams of the various couplings:

 

 

[The Bigbee Line]

This is an emergency screw coupling, correctly painted red.  There is no flat for the Gedges slot...

 

Used to couple vehicles without a coupling in an emergency, hence name.  On coaches a failed buckeye auto coupler would be rejoined with this.  There were other obscure times it would be used.

 

[russ p]

Instanters can only be put in the short position when coupled to other instanter fitted vehicles.

This led to an undesirable situation when EWS put swing head fitted 66 on MGRs so the wagon coupling had to be used, an instanter.... In the long position

[The Bigbee Line]

This page from the Southern Region User Catalogue shows the coupling on the 4-SUB and the Emergency Screw, made from 2 short links.  Each component part had its own drawing and catalogue number...

 

[The Bigbee Line]

Instanters can only be put in the short position when coupled to other instanter fitted vehicles.

This led to an undesirable situation when EWS put swing head fitted 66 on MGRs so the wagon coupling had to be used, an instanter.... In the long position

Quite common on the Southern Region when Instanter Coupled wagons were hauled by a 73 or 33/1.

[The Bigbee Line]

Last one for tonight.

 

This the end of what was built as a Freightliner 'conventional'.  No hole in drawhook so the coupling lived on the bracket to the right of the drawhook.  This one also has another on the drawhook.  No gedges slot and traces of the original green paint.

 

 

 

https://www.flickr.com/photos/55938574@N03/12597390094/in/album-72157641126609655/

Edited August 17, 2017 by The Bigbee Line

[jim.snowdon]

The couplings on the original Freightliner wagons (and possibly some of their successors) are atypical by virtue of having a pivot joint incorporated in the drawhook, rather than the usual arrangement of allowing the drawbar to swing from a point around the drawbar spring. Adopting the usual arrangement of anchoring the coupling in the drawhook would have made it longer, which would in turn have meant either longer buffers or putting them on extended bases. All in all, a bit of a pig's ear of a design. Using a short coupling hook to hook was probably the better solution overall, given that these wagons led fairly sheltered lives compared to the general use fleet.

 

Jim

[The Johnster]

Are you sure? I thought the emergency couplings specifically did not have this feature so that they could not be used to replace a normal coupling. This would be important since the emergency couplings would be shorter as they would go hook to hook, which is a shorter distance than a normal coupling that would go hook to hole.

 

You are right and I am thinking of spare replacement screw couplings; the emergency ones went hook to hook.  It was a long time ago, in a galaxy far, far, away...

Edited August 18, 2017 by The Johnster