these two classes that were rebuilt gained a cab. Unrebuilt locomotives retained their narrow cab. By 1948, the service was sixteen trains, of which seven were fast. An additional three trains ran as far as Wadhurst. In 1957, the service was eighteen trains daily, of which nine were fast. There were nine trains on Sundays. The Schools Class locomotives worked the line until 1957 when steam was withdrawn on the Hastings line. Diesel-electric multiple units of what became British Rail Class 201, 202 and 203 (the "Hastings Diesels") took over working the route. Under British Railways, classes D1, E1, H, N1, M7, Q, Q1, Std 3 2-6-2T, Std 4 2-6-0 Std 4 2-6-4T and U1 were permitted to work between Tonbridge and Grove junction. Freight trains from Tonbridge West Yard were not permitted to depart until the line was clear as far as Southborough Viaduct. Other classes of locomotive known to have worked over this section of line include C, and E4. Diesel-electric era (1957–86) Special narrow bodied diesel electric multiple units were introduced in 1957–58 to replace steam traction. British Rail Class 201 (6S), 202 (6L) and 203 (6B) (the "Hastings Diesels") took over working the route. These units were constructed of narrow rolling stock. They were delivered in six-car formations (the 6Bs including a buffet car) and two units were often operated in multiple to form twelve-car trains. In latter years some of the units were reduced to five, and later still, to four cars. The 6S units were intended to be introduced into service in June 1957. On 5April a fire at Cannon Street signal box disabled all signalling equipment there. As a result, locomotive-hauled trains were banned from the station. A temporary signal box was commissioned on 5May and the 6S units were introduced on peak services the next day. Two units coupled together formed the 06:58 and 07:26 Hastings–Cannon Street services in the morning, and the 17:18 and 18:03 Cannon Street–Hastings services in the evening. From 17June the 6S and 6L units were working services throughout the day. The 6B units entered service between May and August 1958. The Hastings Diesels had almost completely replaced steam by June 1958. With the introduction of the Hastings Diesels, an hourly service was provided. This split at Tunbridge Wells, with the front portion running fast to Crowhurst and the rear portion stopping at all stations. The service ran