4-RES units, these cars were not formed in the sets in numerical order, and some of the driving motor cars initially ran with other trailer cars as 4-COR formations. The first changes took place during World War II, following the destruction of 25 carriages during bombing raids. This total included the equivalent of three 4-RES units. A number of units were reformed to re-use the carriages that survived from individual units, and after the war was over new carriages were built to replace those destroyed, taking the numbers of the old ones. In total this involved eleven driving motor cars, seven Trailer Thirds, five Trailer Composites, and one buffet car and dining car apiece. This re-arrangement led to the loss of 4-RES units 3058, 3060 and 3063 and the formation of three new 4-COR units, which took numbers 3156–3158. In 1955 4-RES unit 3072 was converted to a 4-BUF unit following a fire in the kitchen car, which was rebuilt as a prototype Restaurant Buffet design for British Rail. In 1961–1962 the kitchen cars in 4-RES units 3056, 3065 and 3068 were converted into Griddle cars. The units involved were given the classification 4-GRI, and in 1964 they were renumbered 3086–3088. In January 1964 the remaining 4-RES units were disbanded and the carriages reformed with former 6-PUL and 6-PAN stock. Between then and the final withdrawal of these carriages at the end of the 1960s a variety of different unit formations were created, including further 4-COR units (numbers 3159–3166), 6-COR (3041–3050), 4-PUL (3054–3059), 4-COR(N) (3065–3071) and 6-TC (601). For further details of this complex period of unit reformations, see here. Accidents and incidents On 3 June 1960, an empty stock train formed by two units of the class overran signals at Waterloo and was in a sidelong collision with a steam-hauled passenger train that was departing for , Dorset. A few passengers suffered slight injuries. Withdrawal and further use Apart from the 4-RES units, which were disbanded in 1964, the 4-COR, 4-BUF and 4-GRI types continued in existence through to the withdrawal of this stock from passenger service in 1972, although the last planned working by 4-COR units on Waterloo to Portsmouth diagrams was on 31 July 1971. Thereafter the underframes of a number of carriages were reused by the engineering department as long welded rail carriers and crane runners. A full list of vehicles affected is below: Preservation One