The uk experimented with metal detector type screening at train stations after our bombings on the 7th july. It doesn't work with you have thousands of people s

The uk experimented with metal detector type screening at train stations after our bombings on the 7th july. It doesn't work with you have thousands of people streaming in and out of the gates- all you do is end up practically shutting down the station. So now they focus on temporary gates and profiling - which turns out to be much more efficient than random screening.