It might be 17/64 based on comparision with AN 10 wheeler. The tender is not proportion right for a PRR E6 or other smaller PRR loco. It is too long but the trucks are a representation of a common PRR truck.
The loco boiler and all looks well done. However, the trailing truck does not look very detailed.
All in all a very interesting piece. A new paint job would dress it up nicely.
To me the motor looks like a Permag motor. In that vintage a Series wound motor would be more common. I wonder if the mechanism has been upgraded. The wheels on the loco might be insulated even though it is set up for outside 3rd. I would check that just 'cause.
