A second round of strike action in as many weeks is has entered its second day bringing continued misery to commuters on Southern Rail this week.
The industrial action will started on Tuesday, with more planned for Friday and travellers have been warned of disruption throughout the entire week.
Here's everything you need to know about travelling during the strike.
What day and time?
Driver strike action started from first thing on Tuesday (13 December) and ends at the end of Wednesday (14 December). There will also be action on Friday (16 December) all day.
There are no Southern Rail service at all on these days, or on the Gatwick Express to Brighton, and the rail operator is advising passengers not to attempt to travel.
Reduced and disrupted services are expected on days other than this over the entire Christmas period.
What services can I expect and where?
Thameslink services will run as usual.
Gatwick Express services to London Victoria will run every 30 minutes from 5am to 10pm.
Routes served by other train companies are expected to be busier than usual and tickets will be accepted.