Several current and former MTA employees have been indicted on charges that they cheated on safety exams.
Thirteen workers, including four from Westchester and one from Orange County, allegedly shared copies of the questions and answers before taking the tests to become train conductors or engineers.
The tests measure how much a candidate knows about critical information such as train traffic signals, speed limits and emergency procedures.
The alleged cheating took place between November 2011 and May 2014.
The exams are part of a required yearlong training program for engineers, who operate the train, and conductors, who are in charge of the train.
MTA officials received a tip that a prospective conductor took photos of the test with his smartphone and shared it with several classmates.
The MTA immediately overhauled the tests, and the agency says that every engineer and conductor is competent and qualified for their jobs.