Trams on the route along Erleigh Road had been withdrawn on 7 August 1932, to be replaced by motorbuses, The overhead wiring on part of the route was altered for trolleybuses, and a Sunbeam demonstrator was obtained in May 1936 to allow driver training to take place. The vehicle was fitted with a skate to allow it to run under the tramway wires between the depot and the test track, and although there was never a public trolleybus service on the Erleigh Road route, passengers were often carried free of charge during this period to provide a taster for the new mode of transport. Trams were withdrawn from the Caversham to Whitley Street route on 15 July 1936, to be temporarily replaced by motor buses while the conversion of the overhead wiring was completed. A formal opening took place on 18 July, with the Mayor driving the Sunbeam demonstrator, now No.1 in the corporation's fleet. The other five vehicles obtained to provide the service were an eclectic mix, with one each from Associated Equipment Company (AEC) of Southall, Guy Motors of Wolverhampton, Leyland Motors of Leyland, Ransomes, Sims & Jefferies of Ipswich, and another Sunbeam. All had lowbridge bodywork by Park Royal Vehicles, with 50 seats on the demonstrator and 52 seats on the rest.
