MA’s Greenbush Rail Line Stays on Track for ’06 Finish

Tue July 26, 2005 - Northeast Edition
Kip Fry

The Greenbush Rail Line south of Boston ceased operations in 1959, so by the time it is up and running again next year, it will have taken nearly 50 years to get back on track again.

That is one of the primary goals for the Massachusetts Bay Transit Authority (MBTA). It has been that long since a commuter railroad has run from South Station in Boston through the communities of Braintree, Weymouth, Hingham, Cohasset and Scituate including the Greenbush section.

Following the southeasterly route of what was once the Greenbush Branch of the New Haven Railroad, as many as 8,400 people are projected to use the line every day. That should substantially decrease the number of drivers on the Route 3 corridor leading into Boston. It will allow 12 round trips between South Station and Greenbush each day during the week and eight on weekends.

But the rail line is much more than just 18 mi. of railroad tracks. It is a complex project that demands not only a new rail line over much of the route, but also crossings over existing highways, and a series of bridges, tunnels and stations. In all, the work is expected to cost $479 million.

Construction started in 2003 and should be completed by late 2006, according to Tom Carroll, director of community outreach of Cashman/Balfour Beatty (CBB), the joint construction company serving as the primary contractor for the job.

The number of grade crossings for the length of the line has been reduced from 40 to 25. Engineers were able to alter the plans for the other 15 crossings to make them overpasses and underpasses. The plan also requires that nine existing single-span bridges that cross highways be reconstructed. They will each have new ballast decks. The abutments and wing-walls also will be new or rehabilitated. One bridge will be entirely replaced and another repaired.

The plan also includes two new tunnels, one of which is being dug by Trevi Icos of Boston. An underpass with an 8,900-ft. (2,700 m) cut is scheduled for Hingham Square that will pass under three different roadways. The route takes the tracks through a historic section of the town, so by digging a tunnel, the appearance of the area will remain unaltered. The tunnels will help reduce the vibrations there. They would have otherwise had a hazardous affect on the older buildings of the district.

Angelo Colasante, project manager of Trevi Icos, explained that he had originally planned to use a soil mix wall on the project. That way crews would be able to create a temporary support for the walls using the existing materials in the ground there. But once they started digging in the area, workers discovered that there were too many boulders there to use the dirt. It was then decided they should use a slurry wall instead and replace the earth with mix.

Approximately 50 to 60 cu. yds. (38 to 46 cu m) are moved from the work site each day, he said, although that amount will increase by the end of the project.

There have been several delays with work on the tunnels, according to Colasante. Permit problems and extra utilities work have slowed things down. On top of that, the archeological digs that were required before any excavations began have unearthed a number of clay pots so work had to stop while archeologists completed their digging.

“I can’t quantify how much time we lost because of that,” Colasante said.

Trevi Icos started the tunnel work in December 2003 and was supposed to finish by July 2004. But because of these work stoppages, workers cannot finish that part of the project until May 2005.

Work on the Hingham tunnel is being done with slurry wall buckets mounted on machines such as American 998 and Link-Belt 518.

A shallow cut tunnel measuring 3,000 ft. (910 m) also has been dug in Weymouth.

Creating safe grade crossings is one the main concerns of CBB. Each one will be equipped with warning systems of flashing red lights, bells and gates.

Train noise will be reduced with six new noise barriers. They will each be 26 ft. (7.8 m) high to reduce the noise levels from the locomotive exhaust stack, the primary source of the noise.

The northernmost section of the route will use entirely new tracks, Carroll said, while farther south through Scituate and other nearby communities, the route from an older line will be used. Those areas will require old track be ripped up and replaced. When completed, it will be a single-track railroad with four controlled passing sidings measuring about a mile each.

CBB also is building seven new stations along the route, a large project in itself. The company will have 800-ft. (243 m) high-level platforms and enough parking spaces to accommodate anywhere from 200 to 1,000 vehicles at each location.

Several options to the rail line were considered during the planning process. For one, the “super-boat” alternative would have combined boats with buses and other improvements.

However, the cost would have been 50 percent higher than that of the rail and be four times as much to operate.

Once the MBTA opted for the rail, some opposition was raised in the local communities. Some residents complained that the MBTA inaccurately mapped wetlands around the area to avoid having to deal with environmental regulations. As a way to rectify the issue, tracks are being built on existing railbeds in order to minimize impacts to the wetlands.

Less than 3.5 acres (1.4 ha) throughout the entire 18-mi. (28.8 km) strip will be permanently impacted. As a result, 9 acres (3.6 ha) of wetlands will be restored.

Work also was postponed in 2003 because of concerns that problems with permits and other hurdles could lead to cost overruns. CEG