Work on a new simulation generally begins with a look at a map of railways in the chosen area, getting an idea of where to set the boundaries to give a challenging task but within reasonable boundaries. Then we need detailed maps and track plans for our chosen date, which is often chosen for us by the availability of other data such as Working Timetables and loco turns.
If we’re not looking at the Western or Southern, for both of which there are good sources readily available, usually the starting point is a large scale OS map from the Scottish National library, which is available online. The Great Eastern Railway Society publish a detailed plan of the whole GER system as it was at the grouping in 1923, and for the eastern end of Colchester this plan matched the OS maps until the rebuilding in the early sixties; the western end, though, showed significant differences between 1923 and the OS maps of 1942, 1952 and 1966.
I’m indebted to fellow members of the GERS, notably Bill King, Paul Goldsmith and Roger Kingstone, for helping me to sort out what happened and when – and I was surprised by the answers. For historical reasons Colchester station was built on a severe curve, and in 1933 the LNER began thinking about doing something to ease the curve and thus speed up through trains. After detailed planning, work actually began early in 1939, and the plan was to straighten and lengthen the platforms and build a new double track main line for half a mile or so westwards from the station, the joining the original main line on a gentle curve.
Work proceeded for some months, only to be interrupted by the coming of war. Work presumably stopped almost immediately, by which time, as the 1942 OS map shows, the new section of main line was largely complete, but apart from a connection from the station to some new carriage sidings, no changes had been made to the existing track. What is interesting is that the 1952 OS map, and two surveys drawn in 1956 and 1958, show that nothing had changed since 1942, and it appears that work was only resumed when the electrification project triggered the completion of the rebuilding. It’s hard to believe that a major project was left unfinished for over 20 years!