The North Dorset Railway at Shillingstone, Dorset, took delivery of a unique Wickham four-wheeled railbus on Tuesday, 23rd June.

Set to be a valuable addition to the North Dorset Railway’s rolling stock fleet, it will be converted into a 48-seat passenger coach. What makes this railbus unique is that it was never built as a railbus for passenger use.

Wickham built five four-wheeled railbuses for passenger use, none of which survives, but a sixth was built specifically for use as a track inspection unit, with the recording equipment being designed by electronics company Elliott Brothers. It entered service as a Track Recording Coach in 1959 and, travelling at speeds of up to 30 mph, recorded track measurements on special photo-sensitive paper, with the previous record display alongside for comparison.

The vehicle was later renamed Laboratory 20, and with rubber mountings, springs, and hydraulic shock-absorbers, it was very stable. It was also self-sufficient, being self-propelled, and with the on-board engines providing heating and lighting, and the power needed to run the data collection equipment.

Although none of Wickham’s passenger railbuses survived, Laboratory 20 continued in service until 1991. After withdrawal, it found a home on a heritage railway, but it was not fitted with seats until 2003, and saw more than 20 years of passenger use, including more than a decade at the Lavender Line at Isfield in East Sussex.

In recent years, Laboratory 20 has been stored out of use, but having arrived at Shillingstone, it will be restored, starting in spring next year. Initially, it will be used as part of hauled coaching stock, but if there are no insurmountable problems with the mechanical parts, it will be used as a self-propelled vehicle.

Although no Wickham passenger railbuses survive, A four-wheel railbus built by German manufacturer Waggon und Maschinenbau for the Eastern Region of British Railways operated on the Mid-Suffolk Light Railway in April, and a sister vehicle is being restored to operational order at the Llangollen and Corwen Railway in North Wales.