Six weeks ago, a gunman fired more than 30 shots on a New York City underground train, wounding 10 people.Ten days ago, another gunman in the subway killed a passenger in what officials said appeared to be a random attack.Following the attacks, New York City's mayor, or leader, suggested a high-tech idea: deploy security equipment at subway entrances that can sense the presence of guns.Such machines exist.They can be found at large sports centers, airports and many other places where crowds gather.But security experts say that the use of such technology in New York's huge subway system would be difficult, if not impossible.The machines, called scanners, only provide information.Human security agents would be required at each site to act on the information."You're going to have to tie up a lot of officers doing this," said James Dooley.He is a retired New York Police Department captain who served in the department's transit division."We have hundreds of stations, and the fact of the matter is that putting someone at every entrance to every station is logistically impossible," he added.
