Geoff Stenner
I have used these gearboxes on split axles. Sometimes it is a question of getting the split in the right place, but another option is to turn, or get turned for you a tufnol axle bearing to replace one of those in brass. The whole assembly remains live to one side of the frames, but will not bridge to the other if care is taken with further insulation inside the loco body.
Geoff Stenner