Even bicyclists were hemmed in by gridlock on the first day of the city's SEPTA strike.

Commuters gritted their teeth and chose any means available to make do without public transit when the unexpected strike broke in the predawn hours yesterday.

Besides bicycling, driving into the city or carpooling, many commuters crammed onto Regional Rail lines, whose workers operate under a separate contract than the city division and were not part of the strike.

Nightmarish gridlock occurred on Center City streets during both rush hours, and one bike rider reported that cyclists were forced to ride on the sidewalk, and that some almost fell off their bikes trying to cut between the packed vehicles.

"We were overwhelmed" by the thousands of extra Regional Rail riders due to the strike, said SEPTA spokesman Richard Maloney.

Transport Workers Union Local 234 called the strike at 3 a.m. yesterday, waiting until after the Saturday, Sunday and Monday home games of the Phillies-Yankees World Series had finished.

"It was a shock," Christina Mitchell, 36, of Overbrook, said of the overnight strike, while waiting in overflowing lines to board trains at Suburban Station with hundreds of others.

"I just happened to hear it on the radio [yesterday] morning, and so I jumped up panicked," Mitchell said. "I never got dressed for work so quickly in my life."

SEPTA "made a scene like there wasn't going to be a strike over the weekend, so I wasn't expecting to walk to work this morning," Temple student Edward Redding, 21, said during last night's rush hour.

Redding, who takes the subway from Tasker-Morris to City Hall to work part time at a hotel, had just awakened for his 5 a.m. shift when his girlfriend informed him that Temple had alerted students to the strike by e-mail.

Redding ended up like a pied piper, walking up Broad Street and informing others waiting at bus stops that SEPTA wasn't coming. A mass of people followed him, walking together up Broad Street toward Center City.

A large coach bus drove northbound on Broad Street, regularly stopping at SEPTA stops. Two men walking toward Thompson Street said that the bus driver was giving rides for $3 a fare.

The city lifted restrictions on taxi cabs to allow shared rides, and at the deserted Olney Transportation Center hack cabbies were trying to rustle up business.

Temple student Adrienne Shaeffer, 22, was power-walking down Broad Street toward South yesterday afternoon because she didn't have the money for a cab.

"I paid $15 for a cab ride this morning and I was still late" for class, she said.

James Lee, 73, said that he had to pay a friend $40 to drive him from Conshohocken Avenue in West Philadelphia to Spring Garden Street.

Susan Marshall, 57, trying to grab a cab outside the Olney Transportation Center, said that she usually takes a bus from her home in Elkins Park and then a train from Olney to her job in Center City.

"My sister took me to work on her day off," Marshall said. "So, it was an inconvenience to her - it was a hassle all the way around."

Staff writers St. John Barned-Smith and Christine Olley contributed to this report.