ALCO S-1 and S-3
 The ALCO S-1 and S-3 were 660 horsepower (490 kW) switcher diesel-electric locomotives produced by ALCO and their Canadian subsidiary Montreal Locomotive Works (MLW). Basically the two locomotives differed only in trucks with the S-1 using ALCO's own Blunt trucks and the S-3 riding on standard AAR type A switcher trucks.