Every day, railcars filled with dangerous chemicals that could take out much of Center City move unhindered and unnoticed from one end of Philadelphia to the other.
It's one of the most daunting risks to the city's security - and one City Council may try to stop.
Frustrated by the lack of federal action to secure the nation's rail lines, more cities are trying to take matters into their own hands, considering laws to block the transport of hazardous rail cargo through neighborhoods.
The District of Columbia was the first to attempt to force detours, with Chicago, Cleveland, Baltimore, Las Vegas and now Philadelphia thinking of similar steps. This year, Washington's city council banned rail shipments of hazardous materials through the district. Tankers with poisonous chlorine gas used to pass four blocks from the Capitol.
But the Washington ban is on hold as CSX Corp. - joined by the Bush administration - challenges the legality of the local law in federal court.
Railroads argue that cities have no business interfering with interstate commerce. Regulating interstate commerce is the job of the federal government, and the Justice Department concurs.
The rail industry, too, warns that such hazmat detours would cause chaos in commerce.
"This is a situation that creates confusion and could ultimately bring the rail system to a halt," said Robert Sullivan, a CSX spokesman.
He said industrial customers, like refineries and bulk shippers using the Philadelphia port, need to be able to move materials through the region. In testimony last month before City Council, Sullivan said half the local traffic CSX handles is for chemical customers.
But the fear among local lawmakers and environmental activists is that terrorists could turn railcars carrying dangerous cargo into weapons.
"I'm not a Luddite who wants to go back to the preindustrial age, but there are more opportunities than are being taken to reduce hazards," said Stuart Greenberg, an emergency management committee member in Cuyahoga County, Ohio, which includes Cleveland.
A bill introduced in October in City Council would allow shipments of hazardous materials to customers inside the city - but would prohibit dangerous cargo from passing through on its way to New Jersey or Baltimore.
"If there is an opportunity to reroute some of these hazardous materials, we need to seriously look at that," said Councilman Darrell Clarke, who introduced the bill.
For Russell Meddin, the fear comes down to this: He doesn't like the idea of chlorine tank cars idling next to his Logan Square neighborhood.
And that's just what happens, he says.
Meddin said CSX, which took over the former Conrail rail operations in Philadelphia, often uses the rail line next to Schuylkill River Park to temporarily park trains, often ones hauling hazmat tank cars.
"As someone who uses the park, I'm gravely concerned that hazardous material is brought into residential areas of the city of Philadelphia," Meddin said.
Meddin works for a neighborhood coalition that is battling CSX on another issue: access to the city's new riverside park. CSX is trying to stop pedestrians from crossing its tracks at Locust Street to enter the park.
The neighborhood group - the Free Schuylkill River Park Coalition - alleges that CSX frequently uses a second rail line next to the river as a parking lot for trains when its railyard is busy.
On its Web site ( www.freetheriverpark.org), the group has photographs of parked hazmat tankers, as well as a video clip of a chlorine gas car slowly passing the park on the western edge of Center City.
"Not even an accident, but just a malfunction of a tank car could kill hundreds or thousands of people," Meddin said. Earlier this year, a rail accident involving a chlorine tanker killed nine people and injured about 250 in Graniteville, S.C.
"If this happened anywhere in Center City, it would shut down the city for weeks," Meddin said.
Al Caporali, a community activist from Southwest Philadelphia, is also alarmed by hazmat tankers routinely parked for upwards of an hour near his home.
On a recent walk to Bartram's Garden, Caporali came upon an idle four-block-long train of tank cars. He said the train, hauling flammable liquefied petroleum gas and ethylene oxide, sat for more than an hour between the busy garden and a public housing project with 500 families.
"Since 9/11, there's a whole new dimension," Caporali said, "and there should be more precautions."
City Council would also like to know what hazmat cargo CSX is parking in Philadelphia neighborhoods.
If only CSX would provide answers.
Last month, City Council subpoenaed local CSX officials to appear at a hearing. But CSX sent only Sullivan.
When asked in an interview about chlorine tankers parked next to parks or residential neighborhoods, Sullivan was not specific and answered that CSX follows all federal regulations dealing with such materials.
"We comply fully with all the appropriate regulations that govern rail operations, particularly including those involving the movement of hazardous materials," he said.
Since 9/11, the federal government has spent billions tightening security at the nation's airports. It has imposed stricter rules, too, on the maritime industry. In ports, the Coast Guard now escorts most tankers hauling hazardous cargo.
But the rail industry is getting neither the federal funding for improving security nor the same degree of government scrutiny, homeland security experts say.
After 9/11, CSX installed new surveillance and detection equipment at critical points in its network, Sullivan said. It also has trained 87 Philadelphia firefighters in handling hazmat emergencies, and retrained its own police force in terrorism measures. CSX has 135 police officers in 23 states and covering 21,000 miles of rail.
"It's not as visible as airlines or ports, but there's been a great deal of work being done," Sullivan said.
Yet the low profile of the changes has meant some cities have no alternative but to impose their own laws.
"They're responding in part to a vacuum - a vacuum the federal government has the authority to fill," said Richard Falkenrath, a former deputy homeland security adviser to President Bush and now an analyst with the Brookings Institution.
Falkenrath said the federal government suffers "a certain timidity" about issuing regulations to railroads. Airports and waterways are within the public domain, but railroads are in private hands, he said.
"A rail line is private property," Falkenrath said. "While there is a measure of federal regulatory authority, there is nothing like the institution of the Coast Guard."
Peggy Wilhide, a vice president of the Association of American Railroads, said the rerouting of hazmat trains would create gridlock.
"Think of what would happen if Washington did something, and Baltimore and Philadelphia," Wilhide said. "It has a domino effect up the line to where it would virtually stop the movement of these materials."
Fred Millar, an advocate of rerouting and consultant to Friends of the Earth, said other rail companies have lines around Philadelphia that CSX could pay to use.
"That's the crux of the matter," Millar said. "They don't want the government to tell them to shift from one railroad to another."