Sixteen cattle boxes were built at Earlestown Works in 1902 for use in passenger trains. A further example was built in 1912 to replace a D23 accident victim. They were 22ft long over headstocks with 11’ wheelbase and a tare weight of 8 tons 13cwt 3 quarters. Open fronted oil axleboxes and a wooden underframe, which was common practice at the time of manufacture, were original equipment. The tie rods were removed by the late 1930s. The drawing above shows a gas lamp top, although all photographic evidence indicates an oil lamp was fitted.
The standard brake equipment for these vehicles was vacuum with a Westinghouse through pipe. The kit is supplied with the horizontal vacuum brake cylinder and also the more conventional vertical type. As with many LNWR vehicles of the time, the two types of brake cylinder were used indiscriminately, but no records are available to say which vehicle had which. Two of the examples that reached BR ownership had vertical cylinders but it may be that these were fitted by the LMS. Alarm gear was not fitted until about 1908. The handbrake gear as built was a single lever on one side with a drop arm pushing on one brake shoe only. This was modified sometime after 1912 to comply with new regulations.