It's been several years since I visited the gorgeous & largely empty Worcester Union Station. There is plenty of room in the ROW to the west of the station for a pocket track; I assume that part of the ROW is either P&W or B&M. Would require moving track around, perhaps reinforcing bridges?
Creating stub tracks east of the station is certainly feasible, but would require fill and widening the railroad bridge over Grafton St. The existing "layover" facility is well east of the station and lower in elevation, and obviously requires awkward switching moves to get to the station track. Here is an old public-domain layout of the station from page 90 of "Passenger Terminals and Trains", McGraw-Hill, NY, 1916, by John A. Droege. As you can see the station was built for three
tracks on the Boston east-west line and five
tracks on north-south line, all accessible without walking across any tracks.https://upload.wikimedia.org/wikipedia/ ... r_plan.jpg