Transport for London has rehired EDS and Cubic as IT suppliers for the Oyster card, on a cheaper deal covering the next five years.
The suppliers were the two main firms in the Transys consortium, which was supplying the system but was fired in August, a month after system failures corrupted London travellers' Oyster cards, used for travel on public transport. As a result, at the time TfL had to allow passengers free travel around the city.
Fujitsu and WS Atkins, the other two suppliers in the consortium, will leave in 2010.
The value of the new deal has not been disclosed, but TfL said it was saving money through the new arrangement. It has also acquired the rights to the Oyster brand, of which six million cards are currently in circulation.
Since the system problems in the summer, a number of alternatives to Oyster have been proposed, including special RFID phones that could also be used for contactless payments in some stores.
But the current announcement means commuters will continue to be able to use their Oyster cards "for years to come," according to Shashi Verma, TfL director of fares and ticketing.
TfL said the cost savings were part of a £2.4 billion (US$3.5 billion) efficiency plan announced last week.