The Siemens press release and the DfT press release contain impressive statistics for the additional capacity that this train will provide - for example 60% more carriages into London Bridge. It is not clear, however, whether this is achieved just by train lengthening, or whether this figure is achieved by including the existing Southern services that will transfer to Thameslink.

It is noticeable that comparative figures for seats into London Bridge are missing from the press releases. The 12-car Electrostar trains currently used by Thameslink have 798 seats each, whereas a 12-car class 700 has 666. So what is the secret of the DfT solution to overcrowding on the Brighton Main Line? Quite simply, it is more standing space. A 12-car Electrostar has a theoretical capacity for around 534 standing passengers, whereas a 12-car class 700 has a claimed capacity for 1088 standing passengers.

There is no doubt that this will be a high quality, well engineered product. In essence it is a metro train, designed for short-distance high-density commuter traffic - the picture above shows the relatively narrow seats, wide gangways and standbacks at the door vestibules. Ten years ago, in October 2003, the Seventh report of the Transport Select Committee stated that "for journeys of more than 20 minutes, capacity equals the number of Standard Class seats". However journeys between Brighton and London take around an hour, for which more passengers will be expected to stand.

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