Commonwealth Avenue Superstructure Replacement over 1-90

Boston, MA

Project Highlights / Scope of Work:

  • Required meticulous pre-construction coordination and scheduling with GC, numerous subcontractors and MBTA to complete scope of work within 17 day shutdown of MBTA Green Line, Eastbound Commonwealth Avenue, I-90 & MBTA Commuter Rail
  • Work occurred in heavily populated area of city requiring immense pre-planning to avoid logistical issues of material delivery and equipment mobilization
  • Constant coordination and communication required on-site during construction with all parties to sequence work tasks in efficient manner to remain on-schedule
  • Removed 1,900 TF of existing ballasted, concrete tie track on bridge approaches
  • Furnished and fabricated 5,300 LF of new Flash-Butt Welded Continuous Welded Rail (CWR) strings
  • Installed 1,900 TF of new ballasted, wood tie, CWR track on bridge approaches, including Curved Rail Expansion Joints with ZLR fasteners to account for horizontal bridge movement
  • Surfaced, aligned, dressed and thermally adjusted 1,900 TF of new ballast track
  • Installed 225 TF of full-depth rubber panel grade crossing
  • Gauged, lined and profiled 1,540 LF of new CWR using top-down rail hanging jigs in pre-formed rail troughs on cast-in-place concrete bridge deck
  • Utilized 2-part SIKA ICOSIT 340/45 Polyurethane Grout for first time on MBTA Railroad to encapsulate 770 TF of new rail in 2 lifts without the use of permanent steel fasteners
  • Portions of track construction performed under catenary wire territory
  • Work was completed within allotted schedule duration per contract

Project Description:

Railroad Construction Company, Inc. (RCC), as a subcontractor to Walsh Construction Company, completed the replacement of Massachusetts Bay Transportation Authority (MBTA) Green Line B Branch tracks during the highly publicized first summer shutdown for the Commonwealth Avenue Bridge Superstructure Replacement project in Boston, MA. Utilizing Accelerated Bridge Construction (ABC) techniques, the bridge superstructure and accompanying MBTA railroad tracks were replaced within a 17-day shutdown of the MBTA Green Line and Eastbound Commonwealth Avenue. The MBTA approach tracks leading to the bridge and heavily used Carlton Street Grade Crossing were also replaced and returned to service at the completion of the shutdown.

Utilized for the first time on the MBTA railroad was the application of SIKA ICOSIT Polyurethane Grout. This material was installed to encapsulate new CWR track placed in a pre-formed concrete trough on the bridge deck. This was accomplished using rail-jigs in a top-down track construction sequence. The ICOSIT was placed in two lifts, one poured into the web of the rail to encapsulate the base to allow removal of the rail jigs, and the second to bring the ICOSIT material to final grade, forming a flange way on the gauge side. The ICOSIT material alone holds line, grade and gauge of the track to the bridge structure, eliminating the need for permanent fasteners. In addition, 1,900 ft of new ballast, CWR track was installed on the bridge approaches to tie-in the new construction. New curved rail expansion joints were installed on the west side of the bridge with Zero-Longitudinal-Restraint fasteners to account for any thermal movement of the bridge structure.

Working closely with Walsh Construction, MassDOT and MBTA, the project required months of pre-planning and sequencing to ensure a successful shutdown. While on-site, constant communication with the general contractor, numerous other subcontractors and MBTA was imperative to safely and efficiently complete the work to the satisfaction of all parties.