I would love to know that as well Rog, but havenīt been able to lure it out of him...
I strongly suspect that it is some sort of "standard" DC motor, fitted in a Gintschel manufactured cover, but have no idea of the source.
Back when i got mine, as i grew tired of dismantling my hammer accessory, the possibility of adding the hammer motor as a standard accessory was discussed, since it works perfectly for powering nearly any toy steam accessory from the Tornado plant.
We even named it "DynaMotor", since it so nicely doubles in both roles. Guess it got forgotten during Karstenīs break, after the Wilesco adventure, since i havenīt seen him list it on Ebay.