Call it 40.5mm.
Wheel diameter looks about 12mm tread, 14mm flanges.
About 30.5 mm from axle center to outside end of chassis/frame.
Chassis/frame looks 100.5 mm long overall.
(oops, originally typed 200.5)
Call it 38mm wide over the molded on steps.
Top of deck looks about 17mm above railhead.
You are familiar with the internal arrangement, yes, no?