Was there a plan to add on the branch line from Bletchley to Bedford? Or at least some of it? Or have I got that wrong??
Someone in the community is doing it as a separate thing, may be what you're thinking of. https://forums.dovetailgames.com/threads/marston-vale-line-bedford-bletchley.80709/
Liam at DTG also wanted to add a skinned class 150 to do depot runs at Bletchley to represent the Marston Vale branch. However, that was one of the layers as well as the railtours and sleeper services that is on hold until they can improve performance on the route.