First of all I¡¯m no expert but have used servos extensively for quite a few years now. The majority of these are on extension leads, most home made with the wire twisted together. The longest is around 4 meters long, most are between 1 and 3 meters long. This layout does not have any snubbers fitted and all is fine.?
As it¡¯s just the one loco that is causing this problem I think you need to look for the problem with it. My guess would be that the wheel flanges are flashing across to the point blades or another part of the point causing the servo to twitch. Does this loco have deep flanges compared to the others. Also check the back to back dimensions. If the point is immediately after a curve this can lead to the wheels not straightening up and glancing the point blade causing a flash.?
Hope this might help.
