Bob I can't help identify your loco but I would like to offer a solution to your problem. Instead of trying to fix the gear back in place ream the hole out so that its a free wheeling fit on the axle. Then between the bottom of the teeth on the gear and the axle, cross drill the gear so that you can fit a short piece of steel wire. Cross drill the axle either side of the gear and fit 2 pieces of wire , thus making a basic "driving dog", This system works very well with cheaper motors as when changing direction the motor begins to rotate without load before engaging.
gear wheel __ _ __I I___ wire ______I_I______ _______________axle I I I I wire / I_I \ wire