To get round this I bought some double ended M15 motors which are 2mm narrower. Minimum wheelbase 22mm, for 12mm gauge or wider but due to the width of the motor the minimum wheelbase for 12mm gauge is 28mm with 10.5mm wheels, 30mm with 12mm wheels. I can make these with wheelbases from 22mm to around 35mm. When wired together they run faultlessly and could pull a train of at least 10 coaches. I made this pair for an HO tram and made central pivots to mount them, I can do this to order. They can be slightly smaller than a Tenshodo which they will outlast as they have metal gears and bushes.
I sell these as Tenshodo Replacement types or general purpose made to order.
Although rather fast they are good at low speeds due to a low revving N20 motor. These use a double ended motor and drive via 13:1 gear sets, the top picture shows one installed in a Recreation 21 Bow Frame Simplex.
