For as long as seven months, an unknown number of T users were able to ride buses and trains for free without reloading their monthly passes, the MBTA said yesterday,
The free rides resulted from a computer glitch discovered Monday, when the contractor responsible for the T's fare collection system updated its software, said Joe Pesaturo, spokesman for the Massachusetts Bay Transportation Authority.
The software update was conducted to shut off about 13,000 lost, stolen, or expired cards. But it also detected and shut off an unknown number of monthly passes that had been automatically reloaded each month without payment, Pesaturo said.
"The free ride is over, so to speak," Pesaturo said.
Since Monday, the T has heard from several monthly pass holders whose cards no longer worked. All of them, he said, had obtained their passes through the T's corporate pass program.
The owner of one of the automatically reloaded cards -- Allison, 30, of Brighton -- said she realized her luck had run out when the fare gates would not open for her at the Copley T stop Tuesday.
"I had this golden card," said Allison, who did not want her last name used because she had not paid for her $59 monthly pass for about six months. "At the end of the month, when I would go to put money on for the next month, it said the next month had already been paid."
Allison, who did not report her problem to the T, said she purchased the card on her own and not through the corporate program.
The MBTA and Scheidt & Bachmann, the contractor responsible for the fare collection system, are conducting an audit of the entire system to determine how many cards were affected and how much money was lost, Pesaturo said.
"This is the responsibility of Scheidt & Bachmann," Pesaturo said. "Scheidt & Bachmann will have to reimburse the MBTA for . . . any revenue that is identified as lost. The T will not be out a nickel for this."
Executives with Scheidt & Bachmann could not be reached for comment yesterday.
Preliminary results of the audit, which is expected to take a few more days, indicate that the problem was not widespread, Pesaturo said.
Executives with Scheidt & Bachmann have also informed the MBTA that some valid cards were accidentally disconnected in the software update, Pesaturo said.
"Any cards that should not have been turned off, we're turning back on," he said. "Most customers probably won't even notice, because their card will probably be turned on before they tap it again."
Customers who believe they lost value stored on their cards should call the T's customer support services at 617-222-3200. Any lost value will be restored by the T, Pesaturo said.
Ryan Haggerty can be reached at rhaggerty@globe.com.