SAN CARLOS, Calif.--Caltrain last week asked the state of California for $500,000 to purchase cameras that will enable the transit authority to gather data on why six people have died on its tracks so far this year.

The transit system will use the money to install cameras on the front and back of its 30 trains that serve San Jose, San Francisco and Gilroy, Calif. Information extracted from the cameras will help officials record suicides, which represent more than half of the fatalities each year, and other deaths in the same way police cameras record arrests for drunken driving, said Christine Dunn, a spokesperson for Caltrain.

"We want to keep people off the tracks," Dunn said. "We can study how people are getting on the tracks, where they are getting on the tracks, and then develop plans to deal with it."

The latest death reported in the tracks was in late April when a train hit a trespasser walking on the rails in the Atherton Station near San Jose, Calif. Caltrain's deadliest year came in 1995 when 20 people died.

The transit system is combining the cameras with previous efforts such as installing more fences, educational videos, ad campaigns and suicide prevention walks. The $500,000 will only be used for the cameras, however.

Using the cameras for investigations to develop appropriate procedures is the best way to leverage technology, said Felix Nater, president of security consulting company Nater and Associates.

"I definitely see a value if they are trying to figure out how to protect the tracks or identify if there was an accident or a suicide," he said. "I caution though because it is just one form of intervention that should not stand alone. If they look at the footage to determine where the fencing is inadequate, for example, then the tool becomes more effective."

The cameras will record 24 hours per day, Dunn said.

"This will help us control vandalism too, which is an issue for any railway system," she said. "We can also keep unwanted people out because they can do a lot of damage by planting explosive devices on trains and hopefully these cameras will help prevent that."

The funding will come from proposition B1, a $20-billion transportation bond package that California voters approved in 2006.