A. The strike affects all bus, subway, and trolley service in the city - as well as the Frontier Division buses in Bucks, Montgomery, and Chester counties.

Q. What's still operating?

A. Regional Rail service, Victory Division buses in Delaware County, most operating out of the 69th Street Terminal in Upper Darby; Route 101 and 102 trolley lines and the Norristown High Speed Line; "LUCY" buses in West Philadelphia between 30th Street Station and University City destinations; and Paratransit service are not affected by the walkout.

PATCO trains and NJ Transit buses are running and could provide an alternative for some trips within Center City.

Taxicab operations have even been expanded. Shared rides will be permitted, allowing drivers to accept passengers who have different destinatinos. In addition, limousines, partial-rights cabs and county cabs can serve customers in the city for the duration of the strike, according to the Philadelphia Parking Authority.

Q. Where can I get details about Regional Rail routes and fares? And will SEPTA have enough trains?

A. Go to SEPTA's website, www.septa.org. For schedules, go to: www.septa.org/sip/sip_rail.html. For fares, go to www.septa.org/sip/sip_suburban.html.

"SEPTA is already operating at full capacity," its website advises. "We are working on adding more cars to some of our regularly scheduled trains." Because crowds and delays are expected, SEPTA asks people to adjust their work schedules or find other alternative means of transportation.

Q. Can I buy a ticket on a train?

A. Not during peak hours. "Customers riding during AM/PM peak hours must purchase tickets prior to traveling – there will be NO cash sales on board trains," according to SEPTA's website.

Q. Will my monthly or weekly TransPass be accepted on Regional Rail trains?

A. Only for trips that begin and end inside the city, including North Hills, but not the Forest Hills or Somerton stations. (Those two stations require a Zone 3 fare – ticket or TrailPass.) Within the city, TransPasses will be honored at all times of the day. For trips between the suburbs and the city on the Regional Rails, commuters will need to pay extra or purchase a Regional Rail TrailPass.

Q. What about student passes?

A. Student weekday passes are not valid for Regional Rail trains, SEPTA says. "Students wishing to use Regional Rail service must upgrade their Student Passes to the appropriate TrailPass needed for travel from the Station used. The Student will surrender their weekday pass and receive a credit of $3.13 for each valid day of the pass, towards the purchase of a weekly TrailPass," according to SEPTA.org.

Q. Can I get a refund for a pass I purchased?

A. If it hasn't been used. "Unused Passes purchased prior to the Service Interruption [strike] may be fully or partially redeemed. At the conclusion of the Service Interruption, return instructions will be published," according to a SEPTA brochure.

Q. How much can the alternative taxicabs charge?

A. Riders between Philadelphia International Airport and Center City may be charged the current $28.50 flat rate. On other trips, drivers of vehicles without a meter are to charge $2.50 per mile for sedans, $3 for stretch limousines. The driver should set the odometer to zero before the trip and explain the procedure to any passengers. "The mileage rate for any trip may not fluctuate based on the number of passengers. No charge may be made for additional passengers," according to the parking authority.

Q. How many people are affected by the SEPTA strike?

A. The lines closed by the strike handle an average 938,000 trips daily. Since most riders make round trips, that means more than 450,000 people are inconvenienced. The impact should be lessened today because Philadelphia Public School students have off for a teachers in-service day.

Q. Who's on strike?

A. Transport Workers Union Local 234 representing 5,000 train operators, bus drivers and mechanics.

Q. What are the key issues?

A. Differences over wages and benefits, including employee contributions for their pensions and health care. The last contract expired in March.

Q. Are any negotiations scheduled?

A. No.