A portion of the $2.3 billion project to extend the Green Line to Somerville and Medford has fallen behind schedule.
That's according to the project director, John Dalton, who told the Massachusetts Bay Transportation Authority's control board Monday that work to relocate existing commuter rail tracks likely will go into November. The original schedule pegged its completion by next month.
Dalton said he was confident that work crews would have time to recover from any setbacks and keep the overall 4.7 mile Green Line extension on target to open as planned in late 2021.
The control board's chairman, Joseph Aiello, expressed concern about part of the project falling behind schedule and stressed the importance of getting it done on time.
The long-awaited project is funded by state and federal money.