The NB class is a subgroup of the _N__ class ballast wagons and fills numbers within this group.
The reason for the NB class letters, as a distinct class from N, has not been determined by the author. Perhaps the 'B' may indicate that the wagons were purchased from rail contractors. The first NB wagons were purchased from 'Bamfield' in 1887. However other ballast wagons were purchased from contractors and these were coded as N. It may well be that the 'Bamfield' wagons were not originally purchased from the VR, but came from South Australia as there are stories of ex SAR ballast wagons in use on VR.
All NB wagons were either purchased or placed into rail service between 1887 and 1895 with a single wagon put into service 1901. Most were fitted with trapdoors in the floor. When placed into service they usually took the numbers of scrapped N wagons.
The NB number group was:
212, 214, 215, 231 - 239, 241 - 244, 247 - 254 256 - 260, 262 - 264, 266 - 270, 274 - 280, 282 284 - 291, 293 - 295, 297 - 302, 304 - 307, 309 - 312, 314 - 322, 324, 325, 328, 329 349.
The majority of the these wagons were removed from service between 1908 and 1916.