New Orange Line trains back in service; T says somebody didn't install a bolt correctly at the factory

The MBTA announced this morning it's returning the new Orange Line trains to service after finding that a braking problem on one train last week was because a bolt on one of the eight braking units on one car had been improperly installed at the factory.

Preliminary findings indicate that one bolt in one of the car’s eight (8) braking units had not been properly installed at the manufacturing plant. With safety as the number one priority, MBTA vehicle maintenance personnel started a fleet-wide process to verify that each bolt (24 per car, 144 per train) was properly installed. As each bolt on a six-car train passes inspection, the train is being returned to passenger service. To this point in the inspection process, the issue has not been found in any other braking units.

The one new Red Line train that had been in service remains out of service pending an inspection for the same issue, the MBTA says, adding it will return to the tracks as soon as it either checks out OK or is fixed, should the same problem appear. The T has said that one advantage of buying Orange Line and Red Line cars from the same company is that they are very similar mechanically - the Red Line cars are a bit larger - which should make maintenance similar.