Kevin says it should be identical to the original as far as visible pieces are concerned but invisible pieces were added according to his whim!
These instructions were put together using LDraw. Unfortunately, LDraw is currently missing the chassis/suspension piece that goes either side of the motor wheels so you'll have to imagine putting them on in step 2.
The locomotive is somewhat top-heavy, so it will tip straight over if you try to take it round a corner at full speed. This is partly because Kevin filled up the boiler to stop it being rear-heavy and doing a wheelie under sudden acceleration!
To build this locomotive you only need the pieces in set #4559.