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proper use of three link couplings


colin penfold

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I have been watching the use of 3 link couplings with interest.

 

Can anybody say whether there is a standard procedure for how to couple loco to front vehicle and vehicle to vehicle:

 

Does the link from the leading vehicle go onto the hook of the trailing vehicle?

Does the link from the loco always get used ont the hook of the pulled vehicle?

 

Interested in post ww2 practice.

 

Hope you understand the question and can provide an answer

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The train must always be coupled to the locomotive and never the other way about. Whether using screw-tensioned links, instanters or the basic three metal loops the leading vehicle would have its coupler placed over the draw hook of the locomotive.

 

I'm no rivet counter but I have noticed a lot of modellers hang the locomotive coupler erroneously on this hook. It actually has its own much smaller seating closer to the headstock which in 00 can usually mean fitting the coupleing tight against the buffer beam / headstock.

 

Down the train so far as I am aware it really depended upon what was coupled to what, where and when. A typical goods train might be shunted any number of times and a wagon in its travels might have one or both of its own couplings used or not at different points on the journey.

 

The only time a locomotive coupling would actually be used is to couple one locomotive to another or in emergency if the leading vehicle coupler has broken.

 

Railway professionals please note I am always willing to stand corrected and accept also that practice and rules varied at times and by company or region.

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The loco coupling should always be used to couple to the train. I seem to remember that it was of heavier duty design.

 

For Class 7 and Class 8 freights in the 1970s the instanter link always had to be in the short position, and for any fully fitted freights this also applied.

 

I seem to remember that in the General Appendix of 1972 it states that when coupling 4 wheeled and bogie vehicles in parcels trains that the coupling on the 4 wheeled vehicle should be used (I hope I've got this one the right way round, I'm at work at the moment and I'll confirm when I get home).

 

I tend to always use a screw coupling to couple vehicles if one is screw fitted and the other is instanter. I'm not sure if this was a regulation or not, certainly if vehicles were fitted with continental screw couplings then they should always be used.

 

Apart from the above I think you can use whichever vehicle you want.

 

Edit: Further to consequent replies please see my additional post below.

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Flood is correct, the loco coupling shall be used. (Otherwise you would be stuffed with trying to couple a loco to a set of coaches that only have a dropped buckeye...)

 

Andi (goes off to look for the regs)

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On buckeye-fitted stock the leading vehicle doesn't have a three-link and the situation is different. Locomotives didn't have buckeyes until relatively recently (SR types excepted) but where the loco is buckeye-fitted then I believe that it is the lead vehicle which must have the knuckle "open" to accept the "closed" locomotive coupler.

 

The question relates to locos and rolling stock fitted with the various forms of three-link couplers.

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Well it already looks complicated and it was, and it changed over the years.

 

I'll 'snapshot' 1960 as it's the one I best remember (albeit from a few years later!) and it's the easiest to check - yes I do check this stuff before posting.

 

Loose coupled trains - the wagon coupling is used to attach the train to the engine. The screw coupling of the engine must not be used.

 

When wagons with 3 link couplings are coupled to wagons with screw couplings the 3 link coupling must be used.

 

When wagons with Instanter couplings are formed in freight trains -

1. The couplings must be in the long position in unfitted trains or portions except in the case of loaded cattle wagons in which case the couplings of those wagons must be in the short position,

2. Vehicles with Instanter couplings in fitted freight trains are used in the same way as screw couplings, i.e.they are to be in the short position when marshalled in the fitted portion (and, obviously in the long position when unfitted).

3. The rule regarding couplingInstanter fitted vehicles to screw coupled vehicles is as that for 3 link couplings.

 

It is not permitted to use an Instanter coupling to couple to a vehicle fitted with a buckeye coupling, instead a screw coupling must be used.

 

When a passenger stock or a fitted freight vehicle is attached to an engine or tender the engine or tender screw coupling must be used.

 

Coupled screw couplings must in all cases be adjusted to have the same amount of thread on each side (i.e. where it protrudes into the shackle at the end) - and what it didn't say in the book was that you should ideally have only one and a half turns of thread either side of the central boss.

 

What was not a General Instruction but also aplied was that when tenders fitted with buckeye couplings were coupled to similarly equipped passenger stock the buckeye should be used.

 

Also when it was not possible to use a buckeye for any reason a screw coupling should be used.

 

The situation prior to 1960 was basically the same as that outlined above. The reason for using wagon couplings was simple = they were more likely to break than engine couplings so if a train parted it might be easier to deal with because it was handier.

 

It all began to change in the late '60s and by the 1970s things were getting far more sophisticated for freight trains as newer wagons and heavier trains meant that coupling strength had to be taken into account far more seriously - by the late 1980s we were publishing differing coupling Instructions for different types of wagons by painted number by, in some cases, individual trains.

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Aft'noon all,

 

I've not got the instruction to hand but a memory is stirring re coupling continental vehicles to BR locos and having to use the continental vehicle coupling because the drawhook of continental vehicles doesn't have the protection that BR drawhooks had in preventing the vehicles becoming uncoupled.

 

I'll look for the instruction.

 

Dave

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Aft'noon all,

 

I've not got the instruction to hand but a memory is stirring re coupling continental vehicles to BR locos and having to use the continental vehicle coupling because the drawhook of continental vehicles doesn't have the protection that BR drawhooks had in preventing the vehicles becoming uncoupled.

I'll look for the instruction.

Dave

Continental screw coupling (i.e. the link & pin type) to be used when coupling to 3 link, Instanter, or BR type screw coupling.

When short coupled the coupling to be screwed-up so that the buffer faces are touching but not compressed - no wonder some Shunters never liked them and thought they were a nuisance.

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From the LMS General appendix 1937.

SCREW COUPLINGS ON ENGINES AND VEHICLES ON FREIGHT TRAINS

Except where otherwise provided, screw couplings on vehicles worked by freight trains must not be used for coupling up, unless the automatic brake is in use. This instruction does not apply to the brake van or brake vans of trains or to vehicles provided only with a screw coupling.

Where an engine is attached to loose coupled freight vehicles, the coupling of the leading vehicle must be used and not the screw coupling on the engine.

SCREW COUPLINGS ON CARRIAGE TRUCK, WAGONS, ETC.

Where there are two sizes of couplings that may be used on adjacent vehicles, the larger must be used, provided that the D link is not too large to go into the jaw of the hook of the next vehicle.

In all cases when passenger vehicles have been coupled together, the unused coupling must be hung on the hook provided for the purpose, and under no circumstances must the D link of the unused coupling be allowed to remain in the drawbar hook to which another coupling is being attached.

Where vehicles are coupled together by means of screw couplings, they must be screwed up sufficiently tight to ensure the buffers being brought firmly together.

"INSTANTER" COUPLINGS ON FITTED OR PIPED FREIGHT VANS AND CATTLE WAGONS.

A number of L.M.S. fitted or piped vans and cattle wagons are fitted with the "Instanter" coupling instead of the screw shackle.

Below is a diagram of the coupling when extended for shunting purposes or when used in slow freight trains and the position in which it is to be placed when marshalled on fitted or piped trains, and when cattle wagons are attached to any train.

Shunters and others concerned to see that the coupling is placed in its short position in such circumstances.

Should it be necessary at any time for vehicles fitted with "Instanter" couplings to be conveyed by a loaded passenger train, the "Instanter" coupling must not be used, but only the screw couplings of the other vehicle or vehicles.

VEHICLES FITTED WITH SPECIAL G.W. CO.'S SHORT LINK COUPLINGS.

Vehicles fitted with the special Great Western short link couplings may be conveyed on fitted freight trains.

 

From the BR General Appendix Oct 1960

WORKING OF FREIGHT TRAINS

COUPLING OF ENGINES TO LOOSE COUPLED FREIGHT VEHICLES

When an engine is attached to a loose coupled freight vehicle the coupling of the vehicle must be used and not the screw coupling of the engine.

COUPLING WAGONS FITTED WITH SCREW COUPLINGS TO WAGONS FITTED WITH THREE LINK COUPLINGS.

When it is required to couple wagons fitted with screw couplings to wagons fitted with three link couplings, the three link coupling must always be used, unless the wagons are on a train which is to be screw coupled throughout.

COUPLING OF VEHICLES FITTED WITH SCREW COUPLINGS.

(To much to type out here, covers the tightness, equal threads and proper securing of out of use couplings)

 

Supplement No 1, June 1962, has a bit about continental screw couplings and hydraulic buffers, essentially to the effect that the buffers must be brought just into contact but not compressed, and if there are two different types of screw coupling the one attached to the hook by link and pin must be used.

 

Hope this of some interest

Keith

ps for drawings see http://www.norgrove.me.uk/couplings.htm

for buckeyes see http://www.norgrove.me.uk/buckeye.htm#INSTRUCTIONS

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Continental screw coupling (i.e. the link & pin type) to be used when coupling to 3 link, Instanter, or BR type screw coupling.

When short coupled the coupling to be screwed-up so that the buffer faces are touching but not compressed - no wonder some Shunters never liked them and thought they were a nuisance.

 

At one time in the 1990s, some of the cross channel ferry staff would actually compress the buffers and tighten up the couplings to reduce movement on the ferry. This was considered to be the cause of some otherwise unexplainable derailments at Dagenham where the buffers were unable to slide across each other and the wheels opened the blades of the hand points they were passing over.

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Coupling and Uncoupling of vehicles (General Appendix, October 1972), please see the attached scans.

 

Basically use the loco coupling when the loco is next to coaching stock or a fitted freight vehicle but if coupling a loco to an unfitted vehicle then the vehicle coupling must be used.

 

Instanter couplings to be in the short position if used in the fitted portion and for Class 7 and Class 8 freights the Instanter must be in the short position.

 

Also when a non-bogie vehicle fitted with screw couplings is formed in a passenger train next to a bogie vehicle the screw coupling of the non-bogie vehicle must always be used. Plus the fact that the Continental screw coupling must always be used.

 

post-7112-0-26644100-1352649219_thumb.jpg

 

post-7112-0-24548500-1352649227_thumb.jpg

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Just to be mischevious, can I ask what happened when an unfitted loco, fitted with

three link couplings only, was coupled to a train?

 

Allan F

 

An unfitted loco? Surely all locos are "fitted" in the context of them being equipped with brakes?

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Strictly speaking an unfitted loco is one not fitted with a continuous brake i.e. not vacuum braked or air braked. So as Gwiwer states all locos and wagons were fitted with brakes, it's just that not all of them were fitted with a continuous brake.

 

I know that some shunting locos were not fitted with a continuous brake but I'm guessing that all had been equipped by the time of the 1972 General Appendix. Prior to that then the posts by The Stationmaster and Grovenor are most applicable.

 

Edit: Actually this reminds me of a anomily I realised last night. The Seymour Junction to Willington or Toton coal trains were Class 8 so they needed the instanters to be in the short position. However the lack of substantial gradients meant that the brake force generated from two Class 20s was enough for the rest of the train to not need to be fitted with a continuous brake. Therefore an unfitted wagon may well have been next to the locomotive and the wagon's coupling would have been used - would this have been in the short or long position though? I'm guessing the short position but I don't actually know, it's all very interesting!

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An unfitted loco would only be used on unfitted trains which would generally be loose coupled hence the three links of the wagons would normally be used. The loco could not work the brakes on fitted vehicles so they could only run which the brakes set off. Ok for shunting maybe but not a 'passenger' train.

Don

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Strictly speaking an unfitted loco is one not fitted with a continuous brake i.e. not vacuum braked or air braked. So as Gwiwer states all locos and wagons were fitted with brakes, it's just that not all of them were fitted with a continuous brake.

 

I know that some shunting locos were not fitted with a continuous brake but I'm guessing that all had been equipped by the time of the 1972 General Appendix. Prior to that then the posts by The Stationmaster and Grovenor are most applicable.

 

Edit: Actually this reminds me of a anomily I realised last night. The Seymour Junction to Willington or Toton coal trains were Class 8 so they needed the instanters to be in the short position. However the lack of substantial gradients meant that the brake force generated from two Class 20s was enough for the rest of the train to not need to be fitted with a continuous brake. Therefore an unfitted wagon may well have been next to the locomotive and the wagon's coupling would have been used - would this have been in the short or long position though? I'm guessing the short position but I don't actually know, it's all very interesting!

 

Re-read the 1960 Instructions I posted - the Instanter should be in the long position (and I bet it almost invariably would be as it was far, far, easier to couple that way and it avoided the need to 'flick' it round to the short position).

 

As far as automatic brake fitted shunters are concerned some of what became Class 08 definitely were not originally fitted with vacuum brakes but, like you, I doubt if there were many (any?) shunters in traffic by 1972 without auto-brakes. The main idea originally of not fitting automatic brakes seems to have been on locos intended solely for shunting although they could obviously also work trains - other than passenger trains of course.

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At one time a regular operator of my steam-age layout was an ex-BR freight guard. He never tired of telling that I should always couple the locomotive to the train, not the other way round. I didn't follow his advice as I couldn't pin down the brakes on my models and the train would tend to move away whilst coupling.

 

Why use the locomotive coupling? I can do no better than to draw your attention to pages 59 and 60 of "Fiennes on Rails" written by that great railwayman, Gerard Fiennes, where he is in the brake van of the 2.15pm Whitemoor to Stratford Loco coal and chatting to Arthur, the guard.

 

"'Why do we have to use the engine coupling? [this is Arthur speaking] Its usually a screw-coupling. Its heavier than the three-link. We have to unscrew it to get it on and screw it up again.'

 

Guards, of course, and Arthur was no exception in most aspects of guarding, do the easy thing - except when it suits. So I said:

'Apart from today, the last time you had a screw-coupled brake, did you use the wagon coupling or the other?'

'The bake coupling of course.'

'Why? Its a screw.'

'So you can screw it up tight to the wagon ahead and get a smoother ride - course'

'OK. So there's some sense in the other too. When I was in the Manchester District we had a train in Hadfield loop. When he got the board he couldn't start - train too heavy. So he set back on the brake van to get the couplings loose. Then he reversed and opened the regulator. He shot ahead - light engine. The wagon coupling had slipped off the drawbar hook on the tender.'

'So', said Arthur, 'if he had used the engine coupling, the coupling might have slipped between the second and third, or the third and fourth ... or any of them.'

'So it might. Rules don't make railways safe, only a bit safer than they were. Anyway in the Manchester case when he set back on the brake van the brake didn't hold and the whole train ran back into the sand drag.'

'What happened to the guard?'

'It woke him.'

Arthur looked at me very severely. He is for the grade of guard. My comment was a denigration.

'Anyway', he said, 'its not in the Rules to use the engine coupling,' and he produced his Rule Book. He left me to look, which is why I didn't hear the train start. On a loose coupled train, when the driver opens the regular, clinks on a rising and accelerating note as the couplings pull taut in turn. Clank...clank...clank...clink...clink...clonk. The final clonk is your head cracking up against the ducket, which happens if you are not attending, which I wasn't, being deep in the absence of what I wanted to find in the Rule Book.

Arthur was sympathetic and partly mollified. 'It's in the Appendix' he said.

 

Chris Turnbull

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