CN Diesel Locomotive Classification

CN and VIA use alpha-numeric diesel locomotive classifications in the format: XYZ-nnna where:
X is the manufacturer:
C — Canadian Locomotive Company or Fairbanks-Morse
E — General Electric
G — General Motors (GMD, GMDD, or EMD)
L — Miscellaneous
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
B — booster unit
G — equipped with steam generator for passenger-train service (road switchers)
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) — the sequence in which the members of a given class were ordered by CN. The first batch of locomotives of this type received are normally assigned "a", then "b" for the second batch, and so on.

Examples:

GF-30c — Freight locomotive manufactured by GM, 3000 horsepower, third batch received (CN 5000 is an SD40 of this class).
MPA-18a — Cab unit for passenger use manufactured by MLW, 1800 horsepower, first batch received (CN 6760 is an FPA-4 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 a member of this class).