During World War II a trolleybus branch was constructed from the Oxford Road to Kentwood Hill, enabling trolleybuses to replace motor buses with a consequential saving in precious oil-based fuel. In 1949 the Whitley Street line was extended to Whitley Wood and Northumberland Avenue, and a short branch was built to Reading General station. Subsequent short extensions took the system to its full extent, with the Kentwood route running to Armour Hill and the Northumberland Avenue line running to the junction with Whitley Wood Road.