Altering N gauge coupler height

[JustinSmith]

Does anyone know any way to alter coupler height ?
I have a Lima Class 31 which has sentimental value to me and it couples up fine to my Lima coaches (which also have sentimental value to me as I have had them from new in the late 70s! ) at the "motor end" but not at the other end.
I had some idea of trying to weaken the spring (so the coupling would hang down slightly and therefore be correct) but that turned out to be anything but simple. Quite apart from anything cutting fine spring steel wasn't that easy !

[ntpntpntp]

Should be no problem to snip and shorten the coupling spring with fine cutters (or even scissors), but that won't necessarily fix the problem.

The pickup bogies of those old Lima models use sprung axle pickups and it's those which tend to make one end of the model ride high.  Rather than fiddling with the coupling I used to add more weight above the bogie, using cut up lead sheet.  Nowadays I'd probably use a "fluid lead" type of product (fine lead shot) glued into a plastic or card container.  The additional weight also helped to improve pickup.  I suppose you could try weakening those pickup springs but I don't recall ever doing that. 

Sadly I don't have any photos of such a modification now, the only Lima locos I still have are pristine examples of the later "can motor" versions. 

[JustinSmith]

Should be no problem to snip and shorten the coupling spring with fine cutters (or even scissors), but that won't necessarily fix the problem.

The pickup bogies of those old Lima models use sprung axle pickups and it's those which tend to make one end of the model ride high.  Rather than fiddling with the coupling I used to add more weight above the bogie, using cut up lead sheet.  Nowadays I'd probably use a "fluid lead" type of product (fine lead shot) glued into a plastic or card container.  The additional weight also helped to improve pickup.  I suppose you could try weakening those pickup springs but I don't recall ever doing that. 

Sadly I don't have any photos of such a modification now, the only Lima locos I still have are pristine examples of the later "can motor" versions.

Thanks N.
What you are saying makes sense, though I did try and add weight above the pick up bogie a month or two back (to try and improve pick up) but it seemed to alter the balance of the loco and it appeared to derail more.