Through the Center of Town: Rail Spans Yield to Temp Bridges, Then Tunnel

Thu January 16, 2020 - Northeast Edition #2
Ken Liebeskind -CEG Correspondent

A hammer and loader are demolishing a concrete foundation to prepare for construction of a new drainage system for the downtown rail corridor.
A hammer and loader are demolishing a concrete foundation to prepare for construction of a new drainage system for the downtown rail corridor.
A hammer and loader are demolishing a concrete foundation to prepare for construction of a new drainage system for the downtown rail corridor. A Robbins tunnel-boring machine is used to bore underground lines connecting drainage system pits. Maine Drilling & Blasting drilling minipiles in the rail corridor. Kubricky is constructing a new town sewer line as part of the project. Maine Drilling & Blasting is installing casing inside minipiles and grouting; local company Nop’s supplied the crane and local company Carrara supplied the grout.


The Vermont Agency of Transportation (VTrans), in collaboration with the town of Middlebury, is undertaking a project to replace two nearly 100-year-old rail bridges in the center of Middlebury with a tunnel.

Kubricky Construction, Wilton, N.Y., is the lead contractor on the job, which began in 2017, continued through the 2018 and 2019 construction seasons, and will be completed in 2021 with much of the work set to take place in a 10-week period in the summer of 2020.

Two subcontractors on the job are ECI Construction, Dillsburg, Pa., and Maine Drilling & Blasting, Windham, Maine.

The bridges over the rail line that were built in 1920-21 are deteriorated and were recommended for replacement by bridge inspectors with VTrans. For more than 25 years, VTrans bridge inspection reports documented the ongoing deterioration of both bridges — concrete cracking, delamination and spalling had occurred on all bridge components, embedded steel reinforcement was rusted and exposed, there was leakage through the deck and full depth holes on the Merchants Row sidewalk had to be patched.

The agency decided to remove both bridges in the summer of 2017 and install temporary bridges until permanent structures are built. Both the Main Street and Merchants Row bridges were demolished in July/August 2017 and travel was restored within four weeks.

The decision to replace the bridges with a tunnel was made after bridge rehabilitation was rejected.

"No part of the existing bridge decks and supporting structures are considered salvageable and rehabilitation would not improve two current deficiencies that affect rail — the curved track and insufficient height for today's standard double-stack freight railcars," VTrans stated in a release.

The organization noted that a tunnel offers better safety, drainage and aesthetics and will allow trains to pass through town with less noise.

"The 360-foot tunnel that will replace the Main Street and Merchants Row bridges will address several deficiencies now facing the railroad," VTrans said. "Currently, the bridges do not have enough vertical clearance for double-stack rail cars. By lowering the rail bed approximately four feet, clearance can be increased to 21 feet without impacting the grade of the road and sidewalks above. The tunnel will also enable the alignment of the rail to change, softening the curve that currently exists, allowing better horizontal clearance for trains. Drainage improvements and covering the track will reduce the risk of icing problems that have been severe in some winters as well as ponding that occurs."

The 360 ft. long tunnel will have at least a 21 ft. clearance height for trains. The current vertical clearance for the Main Street and Merchants Row bridges is less than 18 ft.

Kubricky, ECI and Maine Drilling & Blasting built a new drainage system in 2018 and began installing new town water and sewer and storm water lines in 2019. They also are installing minipiles and sheet piling to support the eastern and western abutments of the rail line when it is lowered this summer.

Jim Gish, Middlebury's community liaison for the bridge replacement project, said the bridges were replaced by Mabey modular steel bridges in 2017.

"They were put up to stand for three years and will be replaced by the tunnel in 2020," he said.

In 2020, track and temporary bridge removal is scheduled for May 27 to Aug. 5. Tunnel construction will occur and utilize more than 300 concrete pieces. Roadway reconstruction and railroad track reinstallation also will occur by Aug. 5.

Additional work in 2020 includes welded rail construction, railroad surface and final grading and the initial planting of vegetation.

In 2021 there will be final paving and landscaping.

"All the prep work that was done over the last three years comes into play as they excavate and rebuild the rail line and replace the bridges with the tunnel," Gish said. "The precast concrete will be put in place piece by piece to create the tunnel and supporting lines for the rail line on the side of the tunnel."

When the rail lines are rebuilt, freight trains hauling fuel oil, gasoline and other materials will have safer passage through Middlebury and Amtrak trains will be able to stop in Middlebury.

Amtrak Ethan Allen service currently runs between New York City and Rutland and this work paves the way for trains to come through Middlebury, Gish said.

Middlebury residents and visitors will have to endure road closures during the 10-week construction period this summer.

"Merchants Row will be closed end to end and Main Street/Route 30 will be closed in the downtown area and all traffic detoured," Gish said. "But VTrans and Kubricky are committed to keeping access to downtown buildings open, so we encourage people to come downtown and shop locally during this period."

During the construction this summer, Neighbors Together, a community action group, will oversee a special sale on Wednesdays to promote patronage of downtown shops, among other special events planned to promote downtown shopping. The events, which are being supported by Better Middlebury Partnership, seeks to minimize the impact of construction.

In 2021 there will be intermittent short term lane closures on Main Street and Merchant's Row to facilitate site grading and landscaping and the Triangle Park area will be closed for landscaping.

The road closures pose temporary difficulties to area drivers, but the town of Middlebury will benefit from the project. The $75 million construction tab will be picked up by the Federal Highway Administration (95 percent) and VTrans (5 percent), Gish noted.

"Middlebury is paying the price with five years of construction in our town but we get the benefit of a major infrastructure improvement and we'll reclaim the town green that was lost to the railroad when it was first built," he said. CEG