HS2 and London Midland commuting, part four
Figure 9 (above left) of the October 2013 HS2 Strategic Case compared one-hour-one-way passenger throughput on the West Coast Main Line (at that time) with a situation ‘after HS2’. The simplified diagram (above right) just shows the ac lines commuter capacity in October 2013, and a DfT impression of the situation after the implementation of HS2 phase two.
However, with the further implementation of London Midland ‘Project 110’, in the December 2014 timetable, capacity on the ac lines increased – as shown in column B in the diagram below.
In the evening peak, only a third of London Midland Euston trains run at ‘full length’ (12 carriages). Even in the high peak (5 till 6 pm), most are not full length. If all current peak trains did run at full length, the capacity would be as shown in column C.
The West Coast Slow lines are only signalled for one train every four minutes, but not all available paths are used. If an additional 12-car train ran on the relief tracks, capacity would be as shown in column E.
The October 2013 HS2 Strategic Case sought to associate increased future West Coast commuter capacity with HS2, but the fact is that most Euston commuters do not use the WCML Fast lines in the course of their journey. HS2 would really only be of potential benefit to those commuters travelling to Leighton Buzzard, and beyond.
The number of commuters travelling from Coventry and Northampton into London is small compared to the volumes from Milton Keynes, and points south thereof. But if it were necessary, would it be possible to accommodate a large increase in commuting from Milton Keynes into London, without spending £20+ billion on HS2 phase one?
The answer is yes. One of the most cost-effective approaches would be to run fast trains from St Pancras, reaching Bletchley via a new connection from the Midland Main Line (diagram below). Four Thameslink trains extended to Bletchley would bring the capacity to the level shown in column F above.