F-Line,
1. do you have a map of the Milford secondary between what i assume is Forge Park, Hopkinton & Ashland?
Not really. The Hopkinton Branch was abandoned so long ago the ownership lapsed. I honestly have no idea whose property the rail trail is sitting on, but it's incomplete to Ashland because of chopped-up ownership. You'd have to check a New York, New Haven, & Hartford RR vintage system map for the full path of it.
The north half of the Milford Branch from Milford to Framingham has an ownership gap between Holliston and Milford from an early-70's Penn Central abandonment. That was a real problem for the rail trail to try to piece together over the lapsed section. Holliston-Ashland is still owned by CSX under a railbanked (long-term out-of-service) designation; the state hasn't bought it yet, which is why DCR hasn't done a paved trail. The current makeshift gravel trail has to kick back a couple hundred bucks in monthly rent to CSX from the towns. Ashland town line to the Worcester Line is still active for CSX CP (South) Yard.
2. Is there a connection somewhere to Woonsocket, RI, Blackstone or Webster?
Not today, but it would not be difficult to do. You'd extend the Franklin Line back to Blackstone (abandoned 1968 after the Blackstone River bridge washed out in a flood) with a new river crossing. Not hard to do as the ROW is so well-buffered the SNE Trunkline trail can be very easily relocated off to the side. The line hits a northbound (Worcester-direction) junction with the active P&W mainline on the west side of the river where the old Blackstone station used to be. Install (landtaking of 1 industrial parcel required) a southbound (Woonsocket-direction) wye leg, which merges onto P&W right at the RI state line. It's a little less than 1 mile from there to Woonsocket Union Station.
RIDOT has plans in its 2014 State Rail Plan to study this if it can convince MassDOT to split costs. This would probably be the second-highest leverage de-abandonment for passenger service after Stoughton-Taunton.
3. Would it ever be practical to expand the Franklin Line past Forge Park?
It was proposed to send to Milford and Hopedale, but the Milford Branch is curvy as hell with tons of grade crossings so the schedule would be borderline-intolerable unless those trains did some skip-stopping on the mainline where Foxboro was picking up the schedule slack. One issue with this extension is that Franklin today badly needs a bigger layover yard if its service levels are to ever increase, and the nearest site they could identify for building one was halfway up the Milford Branch in Bellingham. But that's not a good deal if the extension just doesn't add up on ridership or schedule management.
The Milford Branch isn't going anywhere. Grafton & Upton RR, a shortline, is about to take it over from CSX with big plans for new business there. It isn't an abandonment risk at all, and will be there for the long haul if passenger service looks more attractive on second-look.
Seems it might be desirable if the line terminated in Woonsocket, about 11 or 12 miles past Forge Park, or possibly Milford.
One, the other, or both. I think Woonsocket's higher-leverage, but it's pretty much an open book which of those two could be done.
4. Has a possible future extension ever been presented?
RIDOT's studied Woonsocket-via-Franklin before in 2007, though it used some kooky routings no longer available rather than the Franklin-to-P&W one that is fairly simple. That's why they want to re-study. The MPO studied Forge Park-Hopedale in a full workup about 5 years ago, though strangely the results were never published.
So both these options are well-studied, though as per the RIDOT example there's been ID'd need for second-looks and further refinement.
5. Are there plans for extensions, or do informal proposals exist for any of the other CR lines?
Buzzards Bay extension off Middleboro (2011).
Fitchburg Secondary, Framingham-Northborough (MPO, 2002).
North Shore Mall via Peabody/Salem (MBTA, 2004).
various and sundry Lowell Line to NH extensions (NHDOT...every other year it seems as they keep kicking the can).
Bunch more formal studies for abandoned lines--Millis, Central Mass, Portsmouth-via-Newburyport--that are either very much dead now or nobody's idea of a priority because NHDOT is a hot mess.
