Five teenage girls have died this week after being struck by trains while walking on railroad tracks. How preventable these terrible accidents were is an open question, and one rail operators and state and federal regulators must consider.

On Feb. 20, 2010, three girls in Melbourne, Florida (FL), lost their lives when they failed to get out of the way of a Florida East Coast freight train. The girls were about halfway across a rail bridge over a creek when overtaken by the train. Details of the accident reported on include the facts that the bridge came after a curve in the track and that the only devices put in place specifically to keep pedestrians off the bridge were no trespassing signs. The Web site also notes that Melbourne officials have for years considered building a footbridge parallel to the train tracks.

Five days after the tragedy in Florida, a high-speed Amtrak train approaching Philadelphia hit and killed two high schoolers. The accident occurred near a regional commuter rail SEPTA station, where access to the rails must necessarily be fairly open.

The Federal Railroad Administration documented 399 fatal and 314 nonfatal pedestrian accidents involving passenger, commuter and freight trains in 2009. These numbers matched those for 2008, and fall into a category the FRA designates “Trespassing Incidents.”

Recognizing the need to reduce pedestrian deaths on train tracks, the FRA has joined with other public and groups to launch the Trespass Prevention Research Study to determine what rail operators can do to protect pedestrians from unintentional trespassing, and also prevent intentional trespassing. Gates, stop signs and other barriers and warningsproperly used — can keep cars and trucks off tracks fairly effectively. Keeping people on foot from getting onto tracks can be exceedingly difficult, however.

Difficulty is no excuse for not trying. While people need to act to protect their own safety — and that obviously means staying out of the way of oncoming trains — track owners and rail operators need to make it clear to people when they are putting themselves in harm’s way. A couple of no trespassing signs probably won’t do it. Companies must also try to make reaching active tracks as close to impossible as possible.