Rehabilitating West Point's Tunnel

by Robert K. Radske, Supervising Engr.; Mueser Rutledge Consulting Engineers, New York, NY,
Francis Arland, Jr., (M.ASCE), Senior Engr.; Mueser Rutledge Consulting Engineers, New York, NY,
Jeffrey C. May, (M.ASCE), System Engr. of Design; Conrail, Philadelphia, PA,


Serial Information: Civil Engineering—ASCE, 1990, Vol. 60, Issue 9, Pg. 66-69


Document Type: Feature article

Abstract:

Conrail, the Northeast's largest freight railway, had a problem with a tunnel carrying the fastest freight line between the New York area and the Pacific. The 1882 tunnel needed 2 ft more vertical clearance for larger modern freight trains, but the floor was close to Hudson River high water levels and the roof had caved in several times previously, opening sinkholes in the grounds of the U.S. Military Academy. The track was lowered 1 ft to start, the maximum that would still allow gravity drainage to the Hudson. At the beginning of roof work, the existing cast iron liner and portions of the brick liner were removed in alternate 10 ft lengths to avoid cave-ins. Because of Conrail's busy train schedule and the tunnel's single track, work was performed for only 12 hours each day, beginning at 9 a.m. after the passage of TVLA, a high-priority train. Anchors were grouted into the soil overburden for temporary support of the trimmed existing liner; timber bents were also used. The old metal and brick sections of liner were replaced with stamped steel Bernold sheets, which also served as forms behind which shotcrete was placed. Drainage panels were placed between the remaining brick and the shotcrete fill, discharging seepage through weep holes at 6 ft spacings along the springline. Improvements were also made to old drainage drifts, relieving ground-water pressure on the tunnel.

Subject Headings: Tunnels | Linings | Freight transportation | Drainage | Bricks | Soil grouting | Shotcrete

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