In common with most other railway companies, the NBR earmarked certain wagons for transporting locomotive coal. Originally, these were ordinary mineral wagons of the day duly lettered for this traffic. Often any old wagon would do.
However in 1920 the NBR purchased from Hamilton Wagon Company a fleet of 260 12T wagons especially for this traffic. The design was essentially identical to the D97 16/18T mineral wagon, but with both ends solid rather than one having a door. A second order for 250 was placed with Pickering’s making a total of 510 built.
These wagons were numbered in their own 70,000 series and lettered for loco coal. Lettering varied from batch to batch some carrying the legend “Loco Coal Only” with the quatrefoil but no other proof of ownership, and some “Loco Coal” with the more usual “NB” lettering.
This wagon was a long-lived vehicle, with over 400 passing to British Railways. Many of these lasted until the end of the steam era in the 1960s.