For the stock I have built for Foundry Lane I used three link couplings (eventually standardising on the Smiths products after a bit of initial experimentation/trying to do it on the cheap). However the standard coupling adopted for use on New Haden is the Alex Jackson (AJ) coupling. For anyone unfamiliar with these the Manchester Model Railway Society website has a useful page describing them.

When I started to assemble a coal train for the layout I bought a set of jigs for forming the couplings from EMGS, but found that fitting them in the correct position was a little hit and miss and often resulted in burnt fingers. So before fitting the AJ's to my new fleet of sand tipplers I ordered a mounting jig from Scalefour Stores (available on-line, to non-members reference "AJJ" here)

The jig was simple to assemble (although it helps if you read the instructions BEFORE starting to bend some of the parts :icon_redface: ). Photos below show it in use - this wagon is the end vehicle of a train which stays permanently coupled once on the layout so has AJ coupling at one end and three links at the other:

The jigs make light work of forming and fitting the couplings and I only burnt my finger once - which is good news as I think I'll be abandoning three-links in favour of AJ's on the parcels stock for the next project.