Thousands of people in and around Boston arrive at their jobs on a commuter rail system owned and operated by the MBTA (Massachusetts Bay Transportation Authority). To increase its service area, the MBTA decided to reopen the Plymouth and Middleboro lines—which had been closed since the 1930’s. The renovated lines will carry commuters to and from numerous communities on the South Shore. The driving time from many of these locations can be up to two hours or more, but the train ride is less than 30 minutes.
Before the new rail lines became operational, they had to be refurbished to meet current standards. This involved grade crossings over several heavily traveled secondary roads, new layover facilities and approximately 75 miles of new track construction.
Sverdrup Corporation, the consultant commissioned to design the project, saw its greatest challenge being the control of the ground and surface water along the rail lines. Many of the new lines crossed flat terrain, often through wet and unstable subgrade conditions. So, the water had to be constantly drained away in order to maintain a firm and stable subgrade and foundation under the heavy E-80 railroad and impact loadings. Sverdrup engineers determined that they needed a subdrain system that would meet the following requirements: flexibility, high pipe stiffness, nonmetallic, high joint pull-apart resistance, low Manning’s “n” and strip perforation.
Contech PVC TRUSS Pipe was chosen because it met all of Sverdrup’s requirements: TRUSS pipe is flexible enough to adjust to uneven loads, has a 200 psi pipe stiffness to resist E-80 live loads, can be solvent welded to eliminate joint separation, has a Manning’s “n” of 0.009 to maximize flow and has strip perforations.
Phase I of the project was built in the spring of 1995 and included 9000 LF of 12-in. perforated TRUSS Pipe. The Sverdrup engineers and MBTA were extremely pleased with the quality of Contech’s TRUSS Pipe and decided to make it the standard subdrain for all future construction. No other pipe products— including HDPE, SDR 35 PVC or RCP were accepted as an alternative. The project, now known as the Old Colony Railroad, included 6 other phases with over 132,000 -ft. of 12-in. perforated TRUSS Pipe.