October 1971. The locomotives remained ready for service into November but were never called upon. Due to locomotives suffering mechanical defects or in need of repairs, they were often sidelined. Some, such as JA 1271, were used as stationary boilers. These locomotives, as was common practice at the time, were often stripped of parts to keep the rest of the fleet going. North British JA of 1951 History In 1950 it became clear additional motive power was required in the North Island, but the process of dieselisation was yet to begin. Consequently, NZR chose to order 16 steam locomotives from North British to the design of the successful J class of 1939. These locomotives contained a number of differences to both the J class and Hillside JA class locomotives. Although they were turned out with the cross-compound pump, roller bearings on the rods were limited to the connection between the connecting and driving rod, mechanical lubrication was employed. In January 1951 the order had been made for the 16 JA to be coal burners, and North British regarded the order as essentially a repeat order, virtually identical to 1939 J class locomotives. In April 1951 the NZR Chief Mechanical Engineer requested the order to be changed to oil burning due to perceived long term coal shortage due to the 1951 New Zealand waterfront dispute, the associated strike by miners, unavailability of shipping for coal and the expected long term high imported coal price and the long time it would take to build up coal stocks to safe levels, and the class were built as oil burners, with no grate, ash pan or fire door (the only class of locomotives on the NZR to be built completely as oil burners) and ACFL blow down was incorporated late in their construction. A significant improvement was the incorporation of French TIA, blow down equipment which enabled rapid ejection of boiler sludge and reduced the boiler scale, enabling much faster turnaround and higher availability. The system of injection of the oil flow into the burners is different and far more effective than in NZR 1948–1950 conversion of 12 J class locomotives to oil burning. Other detail differences were the use of Stone's headlights and electrical generator instead of the usual Pyle National equipment, the "Butterfly" number boards on the front headlight, and the lack of smokebox number plate (although a smokebox plate was specified