It is important to ensure that all your Lincs couplers are at the same height. In the "rest" position, they should be in contact with the bottom of the buffer beam (assuming a "normal" height beam) and the bit that projects outside the buffer beam must be horizontal with the hook end at 45 degrees to the vertical. To achieve this, the armature can be bent or parts of the underframe trussing can be removed, depending upon the configuration of your wagon underframe (see attached photos, which are of 4mm scale wagons, but the principle applies in all scales),
If anyone has problems fitting or operating the Lincs AutoCoupler, DO feel free to email me for advice. Richard_syms@btinternet.com
Richard Syms, Lincs AutoCouplers