Both CN and VIA use diesel locomotive classification numbers of the form: XYZ-nnna where:
- X is the manufacturer:
- C — Canadian Locomotive Company or Fairbanks-Morse
- E — General Electric
- G — General Motors
- M — Montreal Locomotive Works, Alco, or Bombardier
- Y is the type of use:
- F — freight
- H — hump use
- S — switcher
- Y — yard use
- R — road switcher
- P — passenger service
- Z (this parameter may be absent) is the configuration of the locomotive:
- A — cab unit
- G — equipped with steam generator for older passenger cars
- L — equipped to lead a set of hump units
- T — equipped to trail in a set of hump units
- nnn — two or three digits:
- nn — hundreds of horsepower
- 4nn — locomotive has four axles; nn is hundreds of horsepower
- 6nn — locomotive has six axles; nn is hundreds of horsepower
- a (this parameter may be absent) is the order number. First batch of locomotives of this type received are "a", then "b", and so on.
Examples:
- GF-30c — freight locomotive manufactured by GM, 3000 horsepower, third batch received (CN 5000 is an SD40 of this class)
- GPA-30a — cab unit for passenger use manufactured by GM, 3000 horsepower, first batch received (VIA 6400 is an F40PH-2 of this class)
- GR-412a — four-axle road unit manufactured by GM, 1200 horsepower, first batch received (CN 1400 is a GMD1u of this class)
- EF-640b — six-axle freight unit manufactured by GE, 4000 horsepower, second batch received (CN 2430 is a Dash 8-40CM of this class)
- GH-00a — slug (no diesel engine so zero horsepower) for hump service, built by GM, first batch received (CN 514 is of this class)
