The MBTA pulled all of its new Orange Line and Red Line trains out of service Thursday after a braking system failure disabled one of the vehicles at Wellington Station.

T officials said they decided to take the new trains offline "out of an abundance of caution" while inspectors probe the newest additions to the fleet, which have faced multiple hiccups since they first launched nearly three years ago.

"Earlier today at Wellington Station, a new Orange Line train experienced a problem in one of the train's multiple braking units, and it went disabled," the T said in a statement, italicizing the word "one." "The issue never presented a hazard for riders nor employees, but the train was removed from service for an inspection. While the MBTA works to determine the exact cause of the failure, a proactive decision has been made to keep all of the new trains out of service while the vehicle engineering and technical teams troubleshoot the problem."

An MBTA spokesperson said 64 new Orange Line cars and six new Red Line cars manufactured by Chinese firm CRRC were available for passenger service before the decision Thursday to pull them from the tracks. Each train features six cars. Another eight Orange Line cars and four Red Line cars have been delivered to the T but are still being prepared to join the fleet.

While they are on the shelf, the T will continue to run Orange Line service using "older model trains," prompting the T to project "slightly longer" wait times of trains arriving roughly every eight and a half minutes Thursday afternoon. The T is partway through a multi-year contract with CRRC to replace the entire Red and Orange Line fleets with brand-new trains, which is set to be complete in April 2023 for the Orange Line and September 2024 for the Red Line following a delay.

Some trains are already in service on both lines, though the early arrivers have been plagued with some issues and on several occasions have been removed from service. The decision to pull new Orange Line and Red Line trains from service Thursday also comes as the MBTA faces heightened scrutiny from federal regulators. The Federal Transit Administration is conducting a safety management inspection of the T after top officials in Washington warned they are "extremely concerned with the ongoing safety issues" at the agency.