LNER's operating department required. Not only were they capable of working vacuum braked freights at up to , they could deputise for Pacifics on express passenger schedules. In peak condition a V2 could almost match the Pacifics for sustained high speed running. One locomotive was reliably timed at on the Yorkshire Pullman while another attained on a test train. The V2s were recognised as versatile and powerful locomotives by 1939, but their reputation was more firmly established by their remarkable feats of haulage during World War II. Trains of over 20 carriages loaded to proved within their abilities. On at least one occasion a single V2 hauled 26 coaches from Peterborough to London. Given this capacity for work it was not surprising that construction was allowed to continue through the war years. The V2s performed equally competently for British Railways, leaving their mark on the East Coast Main Line, the Waverley Route between Carlisle and Edinburgh and on the ex-Great Central main line between London Marylebone and Sheffield. Significant modifications were made to the V2 class during its service life. In 1946 a series of derailments was traced to the design of the leading pony truck, which was unduly sensitive to the often poor track conditions, a legacy of heavy wartime use and lack of maintenance. Modifications to the suspension cured the problem. During the 1950s cracks in the 3 cylinder monoblocs became increasingly frequent, but replacing them was expensive and in 1956 the decision was taken to replace the monobloc with separate cylinder castings. Seventy-one engines were thus modified: they can be identified by the presence of external steam pipes from smokebox to cylinders. Finally, around 1960 experiments were made with fitting double chimneys to two V2s. This yielded no significant performance gain, but eight engines were subsequently fitted with Kylchap exhausts. These so-called 'Super V2s' were reckoned to be fully equal in performance to the larger Pacifics. However, plans to fit Kylchap chimneys to the remainder of the class were abandoned once it became clear that replacement with diesel locomotives was imminent. The V2s' swansong came on the Edinburgh—Aberdeen run, working alongside the last LNER A2s and A4s. The entire class was withdrawn from service between 1962 and 1966. Accidents and incidents On 29 January 1939, locomotive No. 4813 was hauling a passenger train which ran into the rear of another at , Hertfordshire. Two people were killed