Firstly, this is not about split gears... it seems Bachmann have found a new way to make their models "fail to proceed" 🙄. I have a new-ish Class 66 (371-379) where the motor spins but the loco doesn't move (makes for a great sound-effect in a double-header 😂 ).
I unclipped the bogies and both have the same problem: the intermediate idler gears that transfer power to the wheel axles were out-of-mesh with their neighbouring gears. The axles for these idler gears are smooth and consequently the gears are free to slide sideways. Also, the width of the bogie's inner channel, where the gears are, is just wide enough to allow adjacent gears to sit on opposite sides of the channel and consequently they don't touch each other. Even if I slide the gears back into a meshed state, the gears soon slide into an unmeshed state again after a few seconds of running the loco.
My questions are:
Has anyone else experienced this? ... what model(s) of loco?
Has anyone taken this up with Bachmann? ... and what was their response?
Is there a way to fix this problem? ...I can only think of looking for miniature washers, or fashioning bushes out of wire insulation, to keep the gears positioned in the middle of the axle.
In the photos below, power comes from gear '1', then to gear '2', then on to gear '3'. However, gear '2' is always unmeshed on the opposite side from gear '1'.