ah nice to see this undertaken , hope the 42 miles isnt too much from Boston to Providence. The Tower 1 Interlocking and the Southampton Yard/LOOP interlocking outside of South Station is probably the hardest part of the route to undertake. If you need help just let me know since i have been in the head end many times for this stretch and i actually live down the street from it.
Interlockings:
COVE (Near Back Bay)
PLAINS (North (well East of in RR Terms) of Forest Hills)
FOREST (Sotuh (West) of Forest Hills)
READ (East of Readville)
TRANSFER (West of Readville and at the south end of Readville Yard)
JUNCTION (just east of Canton Junction)
MANSFIELD (Just west of Mansfield and includes the Framingham Secondary east of the station on Track 1)
HOLDEN (East of Attleboro, 2 to 4 tracks)
BORO (east of Attleboro closer to the station , track 4 only to the CSX Middleboro Secondary)
THACHTER (4 to 3 tracks west of Attleboro , Tracks 3 and 1 only)
EAST JUNCTION (Track 4 only near the old layover yard)
HEBRONVILLE (3 to 2 Tracks , west of Attleboro)
LAWN (West of South Attleboro after the PW (Track 7) has joined and right next to where I95 starts paralleling the tracks)
PAWTUCKET (Tracks to the New Layover Facility and Amtrak Providence MoW base)
ORMS (Just east of Providence station, 2 to 5 tracks)
ATWELLS (5 to 2 tracks) West of the Providence station (Currently the end of the line until a few months from now)
With the new extension on towards T.F Green Airport , Wickford Junction and Kingston RI with a possiblility of Westerly RI.
BRAYTON
CRANSTON
"POST" (New Under Construction near the airport station)
PACKARD
MALCOM
DAVISVILLE
KINGSTON
HIGH ST.
Mainline goes like this:
| Inbound (Track 2) | Outbound (Track 1) | 
Any addition tracks on the Track 1 side have odd numbers (3,5,7,9 etc ....) and any additional tracks on the Track 2 side have even numbers (4,6,8 etc...)