No. 20 was built by the Great Western Railway at Swindon in 1940. It is one of the fourth, and final, basic designs of railcar put into service by the GWR between 1934 and 1942. Weighing 35 tons 13 cwt, this final batch was somewhat heavier than its predecessors, having in addition standard railway buffers and drawer gear. It has twin two-axle bogies, an overall length of 65 ft 8 ins, width 9ft 3ins and height above rail level of 12 ft 2 ins. Accommodation is provided for passengers in two open saloons having a total of 48 seats. There are driving cabs at either end. The angular bodies contrasted with the earlier series which were handsomely streamlined. Their twin AEC diesel engines, each developing 105 bhp and driving its own semi-automatic gearbox, gave a top speed of 60 mph. The railcars were capable of hauling a tail-end load of up to 60 tons.
This particular railcar was also numbered 20 by the GWR. When new it was allocated to Newport (Ebbw) and after a spell in South Wales it went to St Phillips Marsh, Bristol during 1941 and three years later moved on to Yeovil (Pen Mill). It is believed to have been based at Weymouth for some time in the 1950s. In all it worked on the GWR and Western Region for some 22 years . Its final duties were from Worcester shed working on the Tenbury branch, including the last services from Woofferton to Kidderminster on 29th July 1961, and on the Bromyard branch in 1962. It was withdrawn in October 1962 still in its early British Railways 'Blood and Custard' livery.
Purchased by the K&ESR in 1966, it arrived at Robertsbridge on 3 April 1966. Because of width restrictions on the Hastings line, W20W was hauled from Tonbridge by an electro-diesel locomotive, the railcar's body being weighted and tipped to one side, as an ‘out-of-gauge' load. It remains the widest load to have run on that route prior to the tunnels being singled ready for electrification in the 1980's.
After extensive overhaul it was serviceable again by Christmas 1972 and formed the first fare paying public train on 3 February 1974. For the next five years it regularly ran Saturday morning and November services. As restored, its K&ESR livery of chocolate and cream happily coincided with its former Great Western colours. Although in mechanically sound condition, it was withdrawn from service during 1980 suffering badly from corrosion.
Some restoration was undertaken during the 1980s, with the project re-launched under a new team at the beginning of the 1990's. Much painstaking work has been completed but the body has required an almost complete rebuild. The volunteer led project continues, subject to funding.