The 20 busiest underground stations in the Washington, DC Metro system is to get mobile phone coverage from Sprint Nextel.

Customers with this carrier will be able to use their mobiles underground in stations as an attempt to "improve the workday commute for hundreds of thousands of passengers who depend on Metro to travel between their homes and workplaces each day".

While it's bad luck to anyone who enjoyed being out of contact for however long their Metro journey took them, the angle that it will improve response times to public safety issues on the system is hard to argue away.

Sprint says it expects to offer service in the Metro's remaining underground stations by autumn 2010. Here in the UK, some of Glasgow's subway system enjoys O2 coverage.