SAN FRANCICSO – Security gaps around America's freight trains are putting citizens at risk, according to some railway conductors and engineers.
"It doesn't take a rocket scientist to figure out, all they'd have to do is take a pot-shot at a chlorine tanker passing by and you could kill hundreds of thousands of people in one shot," said Tim Smith, chairman of the Brotherhood of Locomotive Engineers and Trainmen.
Every day, trains haul explosives, atomic waste and toxic chemicals like chlorine over 140,000 miles of track, often right through the middle of cities and towns. By one estimate, an explosion of a tanker filled with this substance could kill 100,000 people within 30 minutes.
Outside of Sacramento, at the Roseville Yard — the largest rail yard west of the Mississippi River — rail cars sit idle for hours at a time. The only apparent security at this location is a few "No Trespassing" signs.
But railroad officials insist the rails and the cargo are carefully monitored and guarded.
"Rail transportation is the safest transportation to move goods across the country, and now, more so because of the added security after 9/11," said Union Pacific spokesman Mark Davis. "The rail industry participates in very detailed security discussions on a daily basis with all railroads and homeland security, and we are well aware of movements and very prepared."
While there has been sabotage, Davis said there has never been an act of terrorism on America's rail system. That's proof, he said, of just how secure the railways are.
But in a recent survey, most conductors said they've had no anti-terrorist training, and yards like Roseville seem to be easy targets. Without any fencing to keep people out of Roseville, it was easy for one FOX News reporter to put an object on a passing freight train. The reporter used a pen, but it easily could have been something more deadly.
Security at the Roseville Yard seems to get no better at night. There was no enforcement of signs telling people to stay out on the night a FOX News reporter and cameraman entered the premises, and while they were getting close up shots of railcars and tankers, no one approached the television crew. Even night-shift workers who saw the FOX News camera's bright lights said nothing.
Some conductors, however, fear anyone of these trains could easily be turned into a "dirty bomb on wheels." They say graffiti on the sides of chlorine-filled tankers is proof of lax security.
"It's loaded, it's got graffiti painted all over the side of it. What does that tell you about security? It tells me that nobody's around to shoo them off," Smith said. "And if they've got time to paint their pictures, a terrorist's got plenty of time to plant a stack of C-4's on the side of the car and blow it up."
Critics, including many railway employees, are demanding the government and ownership step up, arguing the industry cannot turn its back on homeland security. Their fear is that it will take something like a London or Madrid train bombing to force the industry to make effective changes.
FOX News' Claudia Cowan contributed to this report.