"This model contains many elements of the classic steam-powered locomotives of the past, including a smokestack, water boiler and driver's cabin."
-- from the employee gift re-creation (set 4002016-1-s6) building instructions
Upgradeable to a motorized engine, using Power Functions sets 8879-1, 8884-1, 88000-1 and 88002-1.
N.B.: The set's box-art reports this set as including 734 pieces - the difference is accounted for by how Rebrickable inventories the train wheel kit.