Couplings

[Kestrel]

Has anyone here tried replacing the standard couplings with 3 link couplings? They obviously work with 4 or 6 wheel wagons where you can mount them on the buffer beam, but where there's a bogie involved, the standard coupling steers the bogie. If the coupling part was removed, would the bogie wander, leading to a derailing?

[jwealleans]

What specfic vehicle are you referring to? I have plenty of bogie vehicles and use screw and 3 link couplings with them with no probem at all.

[billbedford]

Funny how very few full-sized vehicles had couplings mounted on the bogies.

[Hatfield Shed]

Has anyone here tried replacing the standard couplings with 3 link couplings? They obviously work with 4 or 6 wheel wagons where you can mount them on the buffer beam, but where there's a bogie involved, the standard coupling steers the bogie. If the coupling part was removed, would the bogie wander, leading to a derailing?

This is the LNER forum, which business' standard coupling for gangwayed carriages was the 'Gould' knuckle coupler (deployed in the UK from the 1890s on in conjunction with the Pullman gangway, and taken up by the GNR and for ECJS stock, and standardised by the LNER.

Mount Kadees (or competing versions) in the buffer beam of model bogie carriages and they do beautifully; exactly as our modelling friends across the pond have long done, on both passenger and freight vehicles. Take a look at the San Diego HO museum layout if you have any doubts.
https://www.sdmrm.org/

[Trestrol]

This is the LNER forum, which business' standard coupling for gangwayed carriages was the 'Gould' knuckle coupler (deployed in the UK from the 1890s on in conjunction with the Pullman gangway, and taken up by the GNR and for ECJS stock, and standardised by the LNER.

Just to correct you slightly it was Gould gangways then they were changed to Pullman gangways. ECJS TK No12 in the NRM has Goulds gangways, they are similar to Pullmans but without the top prongs. The have surface mounted springs. They are more akin to BR Pullman gangways

[65447]

Has anyone here tried replacing the standard couplings with 3 link couplings? They obviously work with 4 or 6 wheel wagons where you can mount them on the buffer beam, but where there's a bogie involved, the standard coupling steers the bogie. If the coupling part was removed, would the bogie wander, leading to a derailing?

This is the LNER forum, which business' standard coupling for gangwayed carriages was the 'Gould' knuckle coupler (deployed in the UK from the 1890s on in conjunction with the Pullman gangway, and taken up by the GNR and for ECJS stock, and standardised by the LNER.

Mount Kadees (or competing versions) in the buffer beam of model bogie carriages and they do beautifully; exactly as our modelling friends across the pond have long done, on both passenger and freight vehicles. Take a look at the San Diego HO museum layout if you have any doubts.
https://www.sdmrm.org/

The Gould coupler was quite quickly replaced by the 'Buckeye' type, certainly within the first decade of the 20th C (as the Appendices to the WTTs confirm) and standardised on the 3/4 size drop-head with standard coupling hook as patented by WS Laycock of Sheffield in 1899 [GB189903627A].

[Atlantic 3279]

In respect of the originally posted assumption that the bogie-mounted coupling helps to steer the bogie, sometimes it does so in a helpful way, but it can also upset the behaviour of the bogie instead. Tension lock couplings for instance do not pull from dead centre, and under tension they can cause the bogie to crab slightly, pushing wheel flanges at its opposite corners towards the adjacent rail, and even over the rail if the pull is hard enough. A very firm pull or push on a bogie-mounted coupling can also cause the bogie to tilt so that one of its wheelsets lifts and is less likely to follow the line of track correctly. I've observed these effects in practice.
Set against all that is the problem that if you mount couplings on the headstock/buffer beam of a long vehicle, and you have anything but the most gentle of curves, you may struggle to find a combination of coupling length and coupling mounting methods that gives both the freedom to negotiate curves and anything like a realistically close-coupled appearance. Successfully implemented though, couplings on the headstocks can help coach bodies to ride more steadily.
There's no universally best place to have the couplings on all vehicle types, in my opinion.

[Kestrel]

Thank you Atlantic for your detailed scientific reply.

[Hatfield Shed]

...Set against all that is the problem that if you mount couplings on the headstock/buffer beam of a long vehicle, and you have anything but the most gentle of curves, you may struggle to find a combination of coupling length and coupling mounting methods that gives both the freedom to negotiate curves and anything like a realistically close-coupled appearance....

To this end I have been very pleased with the (compatible) close coupling systems found on carriage models from Bachmann and Hornby these past twenty plus years, 'lifted' from European HO practise. The coupling system from 'Keen' works in the same manner, for DIY installation. Linking the coupler pockets with a coupler which locks to form a rigid bar between the pockets enables the gangway faceplates to be in contact on straight or nearly so track, and by a camming action to separate the vehicles proportional to the curve radius; such that a train will go around any curve which the most curve limited vehicle in that train can negotiate. (The new Coronation set has a version of this system judging from photographs.)

That's what I use within my gangwayed carriage trains, with the model buckeye coupler from Kadee each end of the set in the headstock, for its peerless autocoupling performance. The limitation of the Kadee is that a matching centre buffer system - provided by the bottom section of the gangway faceplate in reality - is not possible without some sophisticated arrangement; probably invoving an actuator corntrolled by DCC to release the buffer action to permit uncoupling and coupling up. Room for some progress there to eliminate the slack the Kadee requires, which has the train loose 'coupled' to the loco. But at least the rest of the train moves as a piece.

[Atlantic 3279]

The cam coupling mounts are certainly an option for fitting to existing vehicles, if you wish to add the cost of extra parts and the work to bill for mounting or re-positioning the couplings. Some of the un-necessary cam mounting arrangements that manufacturers have used for loco-to-tender drawbars more recently seem to have been a cause of problems rather than a cure though, causing tenders to crab and derail when the loco is pulling a heavy load.

[Hatfield Shed]

...Some of the un-necessary cam mounting arrangements that manufacturers have used for loco-to-tender drawbars more recently seem to have been a cause of problems rather than a cure though, causing tenders to crab and derail when the loco is pulling a heavy load.

I could ramble on for hours about this...

It's all of a piece that Bachmann and Hornby - both - applied this technique to their carriages, (and in Hornby's case some bogie diesel models) but as far as I can see failed to inform the customer that the supplied tension lock coupler was actually useless for the purpose of reliable coupling, and provided no advice on 'how to' with these coupler systems. (Happily for me, the advantage of continental family and their HO layouts, I knew what to do.)

And now this device is misapplied to tender locos, most of which don't need it anyway; and slack and sloppy where it might be marginally useful on truly big engines such as a W1 or P2.

Bachmann had the class leading solution with a simple drawbar through the dragboxes, and a screw locked slide for spacing adjustment concealed behind the tender frames: neat, simple, effective. I have copied the basic arrangement of drawbar through the dragbox after removal of the defective camming arrangements on P2, V2, W1; and anticipate a few more such until this 'fashion item' is dropped from RTR OO for the worthless junk it is.