Moscow blasts and subway security checks
After today's explosions on the Moscow Subway, new calls may follow for security checks at Russian subway and railway stations. Those who call for this usually give an example of China, where security checks are ubiquitous - you have to X-ray your bags before you enter any station.
However, such a system is absolutely infeasible and would paralyze the whole subway: security checks in China, in fact, are nothing but decorations:
1) Nobody really cares about what you carry in your bag. Liquids etc. are allowed, unlike on the planes.
2) Body search is not carried out on China's subways. You can just carry any weapons or explosives on yourself.
3) Railway stations do have personal inspections, but the girls working there just lightly touch you one or two times, as if they are touching hot iron.
4) Chinese subways have a lot of places where the "sterile area" is separated from the public access area by just a tiny unsecured fence. One could just hand a bagful of explosives over the fence.
Even such symbolic, useless checks create large queues; if real security checks were to be implemented, such as those in the airports, the subway would come to a complete stop: too much time would be required to check each mass transit passenger. There is no way one could search all 7 million people using the Moscow Metro each day: less than a second for each passenger at each station. And still, even airports with their tight security cannot prevent all terrorists from getting on the planes.
The goal of security checks in China is to create jobs; the goal of security checks in Russia would be only to make profit for the security equipment vendors.