More than six months after introducing the new Orange Line trains, the MBTA has announced it is temporarily pulling them out of service.

The MBTA made the announcement Tuesday morning on Twitter, saying that inspectors identified a maintenance issue and the trains were expected to be back in service later in the week.

The new Orange Line trains have been temporarily taken out of service. Inspectors identified a fault with the bolsters which is being corrected to ensure the vehicles are reliable & safe for the duration of their service lives. We expect to return them to service later this week. — MBTA (@MBTA) March 3, 2020

The public transportation agency first introduced the new Orange Line trains in August. The intent is to replace the entire line of 152 trains by the end of 2022 while adding 30,000 new seats to the system.

The new additions are more spacious and have wider doors and updated safety features, according to the MBTA.

This is the third time the new trains have been pulled since the two sets of six cars made their debut in August.

In December, "uncommon" noises were being caused by a faulty "wear pad" at the spot where the vehicle body interfaces with the truck that holds the wheels, according to MBTA officials.

MBTA officials said pulling the new trains this week was not expected to impact service for commuters.

The Associated Press contributed to this report.