The readily available capacity
On 2 April, Alstom UK Director of Government Affairs, Craig Jones, tweeted a “personal view” about the HS2 scheme.
But what does “Euston seats” actually mean?
For HS2 Ltd, it seems to mean, “seats on trains, apart from the dc lines, which use Euston as their London terminus“.
However, the numbers in Mr Jones’ tweet (from the HS2 October 2013 Strategic Case) are dubious. The “current” Euston seats figure is not 11,300. For instance, in the December 2014 timetable, additional capacity was provided on the London Midland services out of Euston.
Furthermore, HS2 is supposed to take over the role of intercity carrier to the East Midlands, Yorkshire, the North East, and eastern Scotland. But the current London terminus of the trains serving those destinations is not Euston.
So “Euston seats”, is a meaningless yardstick. Meaningful comparisons need to be based on the capacity between city pairs, not particular stations.
In HS2’s October 2013 modelled service pattern (below), eleven paths were allocated to places on the West Coast corridor. If all eleven HS2_West_Coast services were full length (“1,100-seat”) trains, there would be a theoretical 12,100 seats. To establish the capacity uplift from high speed rail, the theoretical “With_HS2 figure” would need to be compared against the theoretical maximum “Without_HS2” figure.
Even when compared against ‘readily available’ capacity rather than theoretical maxima from classic platform lengthening or line-of-route resignalling, the benefit from HS2 is unimpressive.
If four 260-metre IEP trains provided the Birmingham intercity service on existing track, the quantum of seats would be (4 * 715 =) 2,860. If eight 11-car Pendolinos provided the North West / Glasgow services, the quantum would (8 * 617 =) 4,936 seats, assuming conversion of one first class carriage to standard.
If four 12-car Desiro (350/2) provided the Outer Suburban Fast service, its seat provision would be (4 * 810 = ) 3,240. If nine 12-car Desiro 350/2 provided the Slow service, its total would be (9 * 810 =) 7,290.
The readily available hourly capacity to West Coast destinations would therefore be 18,326.
The equivalent from HS2 appears to be 27,107 (i.e., 15,007 [West Coast] + 12,100 [from the New HS2 Line]).
The capacity increase is much lower than portrayed by HS2 Ltd. And the “18,326” no-HS2 figure does not include any increases from line-of-route interventions or changes in route utilisation, such as:
- train lengthening or resignalling on the West Coast line,
- providing additional capacity to Milton Keynes, via a link to the Midland Main Line,
- providing additional capacity to the Midlands, by more intensive use of the Chiltern Line,
- diverting Haven Ports railfreight to the cross country F2N route.