Boston school buses appear to be rolling again a day after a surprise strike by drivers stranded tens of thousands of schoolchildren.

The school department said on its website Wednesday that "early indications are that most bus drivers are returning to work."

Television reports showed yellow buses rolling out of bus depots.

Messages left with school representatives were not immediately returned. A message could not be left at the drivers' union headquarters.

The strike Tuesday by about 600 drivers for the school system's transportation contractor caught the city off guard. Drivers say they are unhappy with the way they are being treated by the bus company, Veolia.

Boston schools opened an hour early Wednesday for parents who wanted to drop their children off before work.