Not being au-fait with the area, is there a reason that there are separate bridges over Saxon Street for the two routes, i.e. are they at massively different levels? Seems like you could just shift the chord north slightly and junction to the other line before the potentially double track bridge? It can't be that much of a difference in height as the lines converge not that far other the other side of the bridges.
...just realised I could look at Google Streetview to see, and yes, they are at slightly different levels (looks like slightly less than a metre in difference to me?) I can only presume the is because the station line needs to pass under the Milton Keynes chord from the flyover, setting the hard limit on the maximum separation possible at that point. I presume that to make the gradients favourable the chord to Fenny can't fall more sharply, nor the chord from the station rise slightly to meet it at the same level?
