The narrow-gauge rolling stock classification system is based on the Victorian Railways broad-gauge classifications.

With the prefix letter N to indicate a narrow-gauge car, each class of vehicle originally had code letters similar to its counterpart on the broad-gauge, and all having bogies, most were double-letter identified, e.g. NBB, NABAB, NUU, NMM, etc. The double-letter classification was dropped with the general simplification of V.R. passenger car coding in 1910.

The letters following the N prefix refer to the vehicle's use and type. e.g. A was used to indicate first-class passenger accommodation, B was used to indicate second-class passenger accommodation and C was used to indicate Guard's Van/Brake Van.

Numbers started at 1 for each class of vehicle and progressed in numerical order.

Puffing Billy Carriage NTT

NTT

INSULATED TRUCK. Built in 1899 and numbered 1, it was the only one of its type built.

NAB

COMBINED FIRST-CLASS AND SECOND-CLASS PASSENGER CAR. Four were built during 1906-1909, numbered 1-4. With the cessation of first-class facilities on the narrow-gauge, they were reclassified NB between 1916 and 1923 and renumbered 24-27 to fit into the NB numbering sequence.