Sorry, but Salty is too short for this, and has coupling rods. Also, the shorter part is actually his back, not the front. If you were to use him, the motor would have to run backwards and the coupling would have to be moved to what would normally be Salty's front. A much better option would be to use a (modified) Dunbar from the Chuggington line since the character is (loosely) based on a GP-38 and therefore is closer.
Good luck if you can find any Plarail Chuggers, though. Remember Ucwepn's VR B Class? That was made from two Wilsons, with one's cab at the end of the other.