In a bulletin distributed to passengers, Transit District officials said, "We understand your frustration with the delays in BART service to and from the Hayward, South Hayward, Union City and Fremont stations following the May 10th fires at the Hayward train yard."
The bulletin says, "We realize the reduction in service the fires have forced us to provide is not what you've come to expect and frankly deserve."
BART officials said they hope to restore full service in early August "but we must be upfront and tell you that the repair work is extensive and we cannot yet set a definitive restoration date."
They said regular updates will be posted on BART's Web site and another passenger bulletin will be issued in early July.
BART originally estimated that it would take six to eight weeks to make repairs, which would have meant that the work would have been completed by early July.
BART officials said their initial projections were that service delays between Hayward and Fremont would be up to 10 minutes, but they now realize that "some passengers are experiencing wait and travel times much greater than we first anticipated and announced."
During the repairs, BART trains are leaving the Fremont and Union City stations six minutes earlier than the regular schedule.
Fremont passengers bound for Richmond must transfer onto another train at the Bayfair station in San Leandro.
BART officials, who gave a report to the transit agency's board of directors at their meeting on Thursday, said the loss of control system functions at the stations where the repairs are being performed compromises the operation of their destination signs and some messages are inaccurate.