All in all, the state of CT has a fairly good record of preserving railroad rights of way for further use - restored rail operation or trail use. But they did drop the ball a few times, and one of those when they failed to purchase the line within the town of Portland east of the route 66 crossing next to the freight house. IIRC this section was kept after the c.1965 abandonment of most the line east of Portland to Willimantic, and this line was kept as there was a possible freight customer in the east end of town - think it was a quarry. This stretch of trackage was acquired by Penn Central when they took over the New Haven and remained intact but unused - there was even an approach signal to the swing bridge at Middletown that shined off into the the brush that grew thickly on the old Air Line Main at least into the early 1970s. In 1975 the CT D o T aqcuired the mostly trackless part of the line east of Portland, but they never moved to acquire the Portland track except years later west of the route 66 crossing. At some point the Penn Central (estate) removed the remaining track and [url][/url]finally sold this part of right of way, probably to adjacent landowners, so now there is about a 2 mile gap where the right of way is not under state control - and in some areas it has been obliterated.
All that remains east of Portland trackwise is some yard trackage at Willimantic that saw some use by the P&W after they took over the former Providence line east of Willimantic and was used to store surplus boxcars. After the P&W ended service to Willi, the trackage sat unused until being eventually taken over briefly by the RMNE c 1990. When the RMNE decided not to relocate to that area the yard was soon transferred to the newly formed Conn. Eastern RR Museum, which controls it today as part of their museum complex.