Single bolster wagons were used to carry all manner of long loads including bulk timbers, rails, fabricated steel work and boilers. Generally they ran in pairs but could be seen in threes, fours and even fives as traffic required. Many thousands of diagram D1 were built.
Between 1889 and 1894 the No.6 round-faced grease axlebox was used, changing to the No.2A grease axle boxes in the 1894-1903 period. Thereafter oil axle boxes were fitted. Originally built with twin shoe one side brake gear, a change was made around 1897 to single shoe each side or twin shoe one side Morton duplex brakes. From 1906 the Morton cam brake was used. From 1909, D1 wagons were fitted with the new steel bolster. Brake gear, axleboxes and bolsters could be uprated during repair and it is possible that some wagons were fitted with the Patent swivelling bolster, effectively putting them into diagram D2. Indeed it may be that the swivelling bolster was fitted from 1904 for all new build even though the wagons were still referred to as Diagram D1. The kit includes brake gear components to produce a variety of types, and choice of bolsters and grease axleboxes.
In 1911 the NER owned 8,400 single wagons of which 300 were rated 10T and 6,099 rated 8T. The NER had more single wagons than any other LNER constituent and substantial numbers were passed over in 1923. Around 1,900 wagons remained in service in 1955. On retirement many single wagons were transferred to internal user work on the docks at Tyne Dock, Hartlepool, Hull and Middlesbrough.
The pack contains sufficient parts to build two of the wagons shown in the photo.