Near the village of Steeple Claydon in the Vale of Aylsham is the former station of Calvert. Here England two biggest rail projects will cross. i stress cross there are no plans for an interchange. Here HS2 will in this section follow the route of the former Great Central Railway, England last main line which met the visionary Edward Watkin’s vision of a purpose built high speed main line linking London and the North. At Calvert it crosses the soon to be reopened Varsity Line between Oxford and Cambridge. They will not interchange. A chord was previously built between them to serve a nearby brickworks and army camp.
Why is this? Why are no intermediate stations proposed on HS2 when for comparison the Japanese Shinkansen system has many stations every 30-40 km or so apart, especially around Tokyo.
The reason is the misconception of British railway engineers over capacity. I can say this with some assurance having worked closely with Japanese engineers on High Speed Rail in India. The concept of headway is crucial. The benefit cost ration of HS2 depends on time savings from travel – hence run the trains as fast as possible and as tightly spaced (headway) as possible. It now seems the 18 trains per hour ambition of HS2 is too ambitious, the maximum the Japanese run is 12-14 an hour. Ironically the faster you run the less the capacity, because the headway is dependent on braking and signal technology. The optimum sweet spot seems to be around 300kph as per Chinese railways. Because HS2 is being planned around heavy Spanish and French trains and less advanced signalling technology their headway is far less than lightweight Shinkansen trains which being much lighter take less time to break. The japanese also have a different philosophy around benefits and costs. They realise that commuters are able to pay a premium and the most commuters will be around intermediate stations, even if the houses for those commuters are not yet built. If you can increase capacity by commuters without losing headway you can dramatically increase the farebox and the BCR of the project as the fixed costs serving the major cities will have already been paid for. They do this through interleaving trains and advanced train control. You can switch a train onto the opposite track to overtake a slower ‘stopping’ service, though unless carefully timed this can reduce capacity. The better solution is to have acceleration/deceleration/overtaking lanes before and after intermediate stops – which at around 320kph need to be around 16km in length. Rather than every train stopping at Old Oak Common, Birmingham interchange and Crewe I recommend that such lanes are created around such stations enabling faster services between London and Manchester direct. This would also open up potential for intermediate stations at Amersham, Princes Risborough, Calvert, Stoneleigh (for Leamington and Warwick) and Lichfield, Stafford and Machester Airport – all potential major growth locations. The future strategic plans for the London and Birmingham regions and Oxford-MK-Cambridge should be based around this in the same way Greater Tokoyo’s regional plan is based around Shinkansen. Indeed there is a reason Tokyop-Osaka is the world’s largest city experiencing the economic benefits without the disbenefits that have choked other megacities – you can commute farther and faster by High Speed Rail.
Calvert is a particular opportunity for large Garden City scale development. The best in England. The landscape is flat with few villages. The location is midway between Oxford and Milton Keynes and one of the three routes of the potential Oxford -Milton Keynes expressway. indeed development here could pay for this an improved A road upgradings to Aylesbury and its proposed northern loop road and east and west between Oxford and Luton, linking the M40 to the M1 and linking several growth areas. Indeed I dont think it is really a choice between one or other expressway grade roads, two routes to dual A Trunk road standard with grade separation would perform a better network function and service a wider range of growth areas.
Future decisions on new settlements in the Aylesbury Vale local plan have been put on hold pending decision on the expressway route. Currently Wilmslow (on the Varsity line) and Haddenham (on the Chiltern Line) are candidates. Both are potential Garden Village/town locations and should go ahead – but only Claverty has the opportunity and potential for a Garden City. Were Aylesbury Vale to meet only its own need and that of constrained south Buckinghamshire and Chilterns districts it would not be needed, however there is also the need to meet overspill from London and Greater Birmingham. Oxford and Cambridge have a net inflow of commuters, as well as theior own problems, so they are not good locations for this overspill. The appropriate locations are where peoiple could commute from, on the WCML whose cpacity will increase with HS2, at MK and new Garden City locations north and ssouth of it, at Northmapton and Rugby, and stations along the Marylebone -Snow Hill Line and the suggested stations along the HS2 route.
I suggest calling this new Garden City at Clavert Junction/Steeple Claydon, Watkin, after the great Engineer whose vision was to link the North and Midlands to Europe via High Speed Rail.