in the north west of the colony which saw further line openings, such as the Mildura line in 1903. A new century In 1907, the A2 class steam locomotive was introduced. There were 185 locomotives in this class, and they were Victorian Railway's main passenger locomotive until the arrival of the diesel-electric B class in 1952. On 20 April 1908, the Sunshine train disaster occurred, killing 44 passengers in the worst Victorian railway accident. Electrification of the Melbourne suburban network was also carried out, with the first train running in 1919. By 1924, 210,000 passengers passed through the main city terminal of Flinders Street station per weekday. St Kilda was Melbourne's busiest suburban station with 4½ million journeys, followed by Footscray with almost 4 million, then Elsternwick, Ascot Vale, Essendon and Balaclava. Technology advancements continued, with 3 position automatic signals introduced in 1915, the conversion of screw couplings to knuckle couplers from 1924, and the first remote controlled signalling provided in 1925. The first level crossing flashing lights were installed at Mentone on Moorabin Road in 1932. Despite World War I, significant extensions of rail lines were carried out, particularly in the wheat-growing areas in the north-west and west. The new lengthy parallel lines were considered to be cheaper to operate than the numerous short spurs such as those in the Goulburn Valley. By 1930, the railway map of Victoria was largely complete, with the best land settled and the remaining land marginal for agriculture, with several lines built across the state border into the Riverina of NSW. On November 1937, the first run of the Spirit of Progress was made, a streamlined all air-conditioned train run between Melbourne and Albury, led by the matching S class steam locomotives. From 1924 to 1935, the Better Farming Train made 38 tours promoting improved agricultural practices. The Victorian Railways biggest steam locomotive H 220 Heavy Harry entered service in 1941, at a time when the railways were struggling with the needs of the war effort. In 1943, the Victorian Railways employed 25,450, had 577 steam locos and 12 electric locos on register along with 19,823 goods wagons and 1,499 passenger cars, running along of lines. The network reached its largest extent in 1942, covering 7668 route kilometres. Post war rebuilding After World War II, the railways were run down, with Operation Phoenix unveiled in 1950, involving the expenditure of £80 million over