Commuters are bracing themselves for two days of difficult journeys to work as Southern train services conductor staff strike on Tuesday and Wednesday.
Within London, no Southern services will run between Clapham Junction out to Milton Keynes, or between Sutton and Streatham — other train companies are running services, but they will be busier.
There will be a reduced service between Brighton and London Bridge, and a reduced service 7.30am-6pm only between East Grinstead to East Croydon.
See Southern's website for more details of service disruption and a handy map.
Southern's parent company Govia Thameslink wants drivers to open and close the doors rather than conductors. The RMT says trains are overcrowded and drivers need an extra pair of eyes and ears on the platform.
Govia recently took out an injunction to stop Gatwick Express drivers refusing to drive longer trains with no assistance.
There are more strikes planned for Southern the week commencing 9 May.