ARISTOCRAFT LOCOS

[nico]

This is the area i get the problems

 

[ntpntpntp]

it does deem, through reading various replies that it is the knuckle couplers that are the problem.

I think a lot of it is down to whether the couplings are body-mounted or truck/bogie-mounted. Truck-mounted couplings naturally tend to remain in line with the direction of travel round the curve and can cope with "unrealistic" tight curves, whereas body-mounted couplings are affected by the amount of overhang at the end of the loco or rolling stock and must also incorporate what would be in real life "excessive" swing. Try watching the contortions that two body-mounted knuckle couplings go through when entering a tight curve (or even worse at the middle of an S curve) - it's quite common to see the couplings at 45 degrees to the rails!

Even some small fixed wheelbase locos can have significant overhang beyond the wheelbase that can cause problems. I don't possess one, but the Bachmann 0-4-0 Porter always looks to me like it would suffer from a lot of overhang? I do own a Bachmann 2-4-2T and that has "double-pivoted" body-mounted couplings in order to cope with R1. (Actually they're a bit of a nuisance being too "floppy", so I've pinned one of the pivots now that I run on R3)

Using hook & loop couplings helps to some extent simply because the hook can slide side to side and pivot within the loop.