This is usually the point where I mention my idea again about using the Portland Post Office buildings bordering on Deering Oaks Park for a new intermodal station. Double-track and trench the Union Branch, downtown location, near a 295 exit, improve the Bayside neighborhood.
In response to a post in the Downeaster thread I took another look at the possible locations for future passenger rail stations in Portland. Out of all the possible sites there is only one that really makes sense (other than the PTC/Thompson's Point) and that's the current location of the Cumberland County Sheriff's Office and the Jail. It's non-taxable use right now and the land parcel is clearly large enough to serve the necessary functions along with a parking garage and a nice station.
Relocating the jail is in my mind a "best use" and would also enable the CCSO to have a larger facility that better serves the rehabilitation needs of inmates.