Circa 1930 or later? - Numbers wear off easily but this locomotive can be spotted by slider bar on bottom and skirt between front driver and key.

Note that the motor is back to an Ives clockwork that screws in on the right side. The No 66  looks just like a No. 10 from 1930 except it has die-cast wheels with drive rods and a single boiler band. Below is the same engine with it's No. 12 tender from 1930.