The Vernon Tunnel is another rare engineering structure from Connecticut's first generation of railroad construction. Like other railroads of the period, the Hartford, Providence and Fishkill Railroad had to accommodate numerous pre-existing rural roads when putting through their line. While most roads simply crossed the tracks at grade, at least initially, tunnels such as this were needed when the railroad, in order to maintain a near-constant elevation for its line, constructed a high embankment. Massive ashlar masonry such as that of the Vernon Tunnel was typical of these early railroad structures. The tunnel has outlived the rail line, which was abandoned in the late 1970s.
Vernon Tunnel
This Single lane auto/car tunnel is still in use, whereas the
high embankment above has been fashioned into a beatiful hiking/bike/jogging/walking path. They tore up the disused Rail Road tracks and liked the path with heavy sand. 
From the embankment you look down upon sprawling woodlands and neighbouhood farms.
This Multi-use 'greenway' consists of 5.05 miles of trail along an abandoned railway (Hartford, Providence, and Fishkill RR) from the Vernon/Manchester town line easterly, then southerly to the Vernon/Bolton town line. From Bolton, the railway has been re-graded 15 more miles to Willimantic and is identified as a Connecticut State Trail named the "Hop River Linear Park Trail". In Willimantic, it joins the Airline Linear Park Trail which is approximately 40 miles long. These trails are permitted on Connecticut DEP property.
The original railroad was completed in 1849 and ran for over 100 years. The Rails to Trails project was designed and engineered by the Town of Vernon Engineering Department. Phase 1 of the project funs from Tunnel Road to the Bolton Line and was dedicated in 1995(2.43 miles). This section in Vernon was re-graded by the Connecticut National Guard- Bravo Company of the 242nd Engineer Battalion and was then covered with stone dust by the Town of Vernon. The trail was named "Route Sapper" in honor of the Bravo Company in Vernon. The funding for this project was obtained by the Vernon Hockanum River Linear Park Committee from the State via ISTEA funding, grants and the Boulder Ridge Subdivision sidewalk fund. The trail provides to the public a route for biking, hiking, cross-country skiing, and horseback. Handicap usage is encouraged. The trail is maintained by the Vernon Parks and Recreation Department and by volunteers. Phase 2 of the project, which was dedicated in 1998, runs from Tunnel Road to the Manchester town line and from Phoenix Street to the Tankerhoosen Bridge(2.62 miles). This phase was funded by State and Federal STP enhancement programs and HRLP funds. Phase 3 of the project runs from the Tankerhoosen Bridge to West Road and was dedicated in 2000 (3.19 miles). This part of the trail was constructed by the Town of Vernon Department of Public Works with National Recreation Trails program grants and State LOCIP funding
There is even on the Tunnel Road Embankment section, a very rustc little shed/outbuilding that is a beautiful focal point along the hike.
Or as I like to think of it as "The house in the woods"
SPOOKY!
