There is a limit in Moscow (and other Russian) underground transportation system - you can't enter it carrying your bicycle. You can go biking around, but entering the metro system is no-no. Nothing helps - you can't ask the guard to let you come thru or pay extra to carry it as baggage. So if people get back home late at night and have their two-wheeled friend around they have to do something like this to be able to enter. As a rule the guard is an old lady who won't run for you once you by pass her.