The permanently coupled twin timber wagon was developed in 1882 to combine the features of the double bolster and single wagon. Some 40 wagons (20 pairs) were initially constructed with an additional 408 wagons (204 pairs) added in the 1890s. Forty more pairs were ordered in 1915 and delivered by 1917 with a further 10 ordered in 1919 and delivered in 1921 or later. There were 227 pairs in service in December 1920. The twin wagon was used for a wide variety of traffic including timber and steel sections.
The kit depicts the 1900s version with strengthening to the underframe and sheeting but with the B3 oil axle boxes fitted from 1917 (the later B4 oil axleboxes are available as product code LYRC005). Grease axleboxes are included to represent earlier versions.
Over the years there were few external changes except to the rubbing knuckles which were full width with cross bracing on earlier wagons but 2’8” long on later wagons, and the side sheeting which was strengthened. When the side sheeting change occurred is not known but was most probably with the 1915 drawing. Axle boxes on earlier wagons were Attocks grease pattern but wagons ordered in 1917 and 1919 were B3 oil. It is likely that the 1921 wagons would have been built with B4 axleboxes. In any case it is probable that a change to B4 was made during routine maintenance.
A pack contains parts for two permanently coupled wagons as shown in the photo.