Covid-19: Testing London’s public transport for coronavirus
Scientists at Imperial College London have been using swabs and air samplers to test if Covid-19 is present on the transport network.
Transport for London (TfL) wants to check how effective its cleaning methods are.
Results for previous tests have been negative, but with levels of infection increasing in the community they're trying to find out if that is still the case.
And at the moment passengers in London are being told to reduce their journeys and travel at quieter times.
Research done by the RSSB (formerly Rail Safety and Standard Board) in July, found the chances of catching the virus on a train as 1 in 11,000.