 Both companies were acquired by the city council in the final years of the 19th century, and the routes electrified and converted to double track, and operated as a municipal concern.The City of Hull Tramways (later known as the Corporation Tramways) expanded the electrified tram network along the main roads of Hull up to 1927 when the tram system reached its greatest size.Between 1937 and 1945 the system was converted to trolleybus operation.