Philadelphia, Pennsylvania

Photography Rules
SEPTA Photography & Filming Guidelines states: "The safety of customers and employees is paramount throughout the SEPTA system. While photography is permitted in clearly defined public areas, it is not permitted in any way that may interfere with the safe movement of people or operation of vehicles. ... Photography is prohibited in any area that is not accessible to the public. ... Obviously, these activities are almost always legitimate and that is the end of the issue. However, anyone conducting these activities in unauthorized areas of SEPTA property may be charged and detained for further investigation."
PATCO Photography, Filming & Video Policy states: "Photographers and artists are welcome on the DRPA/PATCO facilities and are expected to be courteous and to use good judgment while photographing or sketching. Recent security concerns regarding all public transportation facilities required a tightening of security procedures in and around the DRPA/PATCO system. The reality of the times has not resulted in a prohibition of photography and members of the public still have the right to take pictures. However, DRPA/PATCO police and other law enforcement officers working under the guideline recommendations of the Federal and State Office of Homeland Security may question persons photographing and sketching transit systems as to their intent (commercial, artistic, hobby, etc.)."
Links
SEPTA South-Eastern Pennsylvania Transit Authority - Official Site. The official site of Philadelphia's transit agency, with maps, schedules, fares, and more.
Philadelphia Trolley Tracks. Info about Philadelphia's streetcar system, including route info, rosters, and photographs past and present. Also suburban trolley systems.
DVARP Delaware Valley Association of Rail Passengers. DVARP is a rail and transit advocacy group for south-eastern Pennsylvania.