If I was in charge of the route selection, a quick glance at the map on my office wall would tell me that I should be looking at a route corridor that should go via Sandy but certainly no further north than St Neots and no further south than Biggleswade. I am not advocating reinstating the Sandy Cambridge section as it was because it was not particularly direct and much of the route is lost. However a more direct route from Sandy joining the Hitchin to Cambridge line at around Shepreth must be worth looking at. This would remove the difficult and costly problem of getting the line into Cambridge. It would also have the benefit of passing Addenbrookes hospital and the adjacent proposed science park which will surely get its own station eventually.
The other option is going via Hitchin which presumably means rebuilding the Bedford to Hitchin line either using some of the original route or following a new route. This does have some merit although it does involve quite a detour. It is effectively two sides of a triangle as opposed to one via Sandy. In rough terms Bedford to Cambridge is around 25 miles as the crow flies whilst Bedford Hitchin Cambridge is about 40 miles. Once you reach Hitchin you then have an existing twin track electrified railway to Cambridge so the new build aspect would be about 15 miles. The question then is do you include Hitchin as a stop which would involve a reversal or do you bypass it to the north and go straight to Letchworth? I am sure Hitchin would have to be included because one of the aims is inter-connectivity with the various main lines it crosses. It would be unthinkable not to have an interchange with the East Coast main line.
The Bedford line approached Hitchin on a shared embankment on the west side of the mainline some of which was used for the Hitchin Flyover. However I am sure this could be overcome and Network Rail stated that passive provision was made for this. The problem would be that if trains from Cambridge to Oxford called at Hitchin, then they would have to cross the East Coast mainline to get on to the Bedford line. So how could it be done without re-introducing the problem that the Hitchin Flyover solved?
This is only my idea and I am probably making it sound simple when there are probably any number of reasons why it can't be done. Rebuild Hitchin station on the other side of Cambridge Road in the former Midland Railway's goods yard.where there is plenty of room. It would be built with four through platforms and two bay platforms. Cambridge trains would use the inner slow line platforms and Peterborough trains could use either allowing two up or two down trains to be in the station at the same time. The bay platforms would be used for East West trains and would be situated on the west side of the main line. As the Bedford to Hitchin line was originally built as a twin track main line, the embankment is wide enough to take two tracks again. One track would go to Bedford and the other to Cambridge via a junction just before the viaduct but after the Cambridge down line has left the ECML. It would only work if the viaduct could be made bi-directional and I am not sure if this would be possible. Cambridge to Bedford trains would then come back over the flyover and into the bay platforms and then reverse. It will be interesting to see what solution the East West Rail Consortium comes up with if the Hitchin route is the preferred one. A "light" option could be just be putting the two bay platforms in the goods yard and providing a link to the main station.
Here is a old photo of Hitchin station I recently purchased.
In the meantime, over the next few weeks I will have a look at what remains of the Bedford to Hitchin line to see what might or might not be possible. I also have some older photographs of the line which I will also put up for illustration and historical interest.
First section from Hitchin through Ickleford can still be quite clearly seen on Google Earth although on the ground it is not so obvious.
A bit further on, the trackbed is clear providing vehicle access to the worksite.