Trains resumed running between the Orange Line's Oak Grove and Sullivan Square stations Monday after nearly a month offline, but the newest train cars manufacturer by Chinese company CRRC will not be among them for at least another three weeks.
The MBTA resumed subway service along the full Orange Line on Monday morning for the first time since a March 16 derailment at Wellington Station. During the nearly four-week span when shuttle buses ran between Oak Grove and Sullivan Square, T crews repaired three miles more of track, replaced six switches, and performed station improvements at the two endpoint stations.
That effort saved 180 days of construction time that the T would have needed if it only did repairs on nights and weekends, MBTA Deputy General Manager Jeff Gonneville said Monday.
Investigators still have not determined a cause of the derailment, which involved one of the new Orange Line trains in passenger service at the time, nor whether the track infrastructure or the vehicle itself is to blame.
Gonneville said the T is testing individual components on the CRRC-manufactured vehicles, one of which is scheduled for three weeks from now, meaning all four Orange Line train sets and the one Red Line set will remain out of service until then.
"There really hasn't been identified a clear issue with the cars that was even a contributing factor to this, but we're being very conservative in our investigation," Gonneville said.
CRRC and manufacturers of other components have provided "very good cooperation" so far, Gonneville said, adding that he hopes to give a "far more concrete update" on the investigation at the next Fiscal and Management Control Board meeting on April 26.