Multiple Orange Line trains were temporarily taken out of service Thursday after being vandalized overnight, the MBTA said.
A T spokesperson said the vandalism consisted of "malicious damage to windows."
"We will be operating with longer headways this afternoon due to a limited number of trains," the MBTA said on Twitter shortly before 2 p.m. "Multiple trains were vandalized last night and repairs are in process."
Get Boston local news, weather forecasts, lifestyle and entertainment stories to your inbox. Sign up for NBC Boston’s newsletters.
On its website, the MBTA says subway schedules are determined by headways -- the time and space between each train. Anytime a train is pulled out of service, dispatchers need to adjust the space and time between the other trains in service.
The T apologized for the inconvenience and said it was working to get the trains back into service "as quickly as possible."
Around 3:15 p.m., the MBTA provided an update saying that repair work and window replacements had progressed at a good pace and they expected to have enough Orange Line trains for the afternoon commute to keep up with the existing schedules.
No further information was immediately available.