The Londond Underground and the Moscow Metro are two of the busiest metro systems in the world, facing increasing overcrowding esp during rush hour.
Some stations in London have to be closed due to overcrowding in rush hour or trains will skip them if there are too many people.
In Moscow, trains arrive and leave every 3 minutes and still they can't take all the passangers.
In Sofia the metro system is also overcowded but not as bad as in the mega cities mentioned above.
Here is a video from the Moscow metro, showing what happens during rush hour.
http://www.youtube.com/watch?v=pp4hPMho7Pw
Some stations in London have to be closed due to overcrowding in rush hour or trains will skip them if there are too many people.
In Moscow, trains arrive and leave every 3 minutes and still they can't take all the passangers.
In Sofia the metro system is also overcowded but not as bad as in the mega cities mentioned above.
Here is a video from the Moscow metro, showing what happens during rush hour.
http://www.youtube.com/watch?v=pp4hPMho7Pw