Commuters are urged to keep an eye out for the first trains running tomorrow, which will be later than normal.
Striking signalers pulled out today over pay, job security and working conditions.
Signalers won’t start working until 7am tomorrow, meaning trains will start later.
The first service from Brighton to London Victoria is at 7:17 am, while the first service from Brighton to London Bridge is at 7:28 am.
A Southern and Thameslink spokesman said: “Following today’s strike, Network Rail signalers will not start work until 7am tomorrow so we won’t be able to start our services until Thursday much later than normal and we will be with changed Sunday timetable.
“That’s why it’s really important that passengers check the service online before they leave the house.”
Angie Doll, Chief Operating Officer at Govia Thames Railway, said: “Unfortunately, due to strikes by RMT members on Wednesday 27 July, we have to once again ask people not to travel unless absolutely necessary.
“There will be very few train connections and some routes will be closed entirely.
RMT general secretary Mick Lynch said union members were “more determined than ever” to improve pay, job security and working conditions.
He said: “Network Rail hasn’t improved what it has paid for so far, and the rail companies haven’t offered us anything new.
“Indeed, Network Rail has upped the ante, threatening to impose layoffs and an uncertain 50 per cent cut in maintenance work if we don’t withdraw our planned strike action.
https://www.theargus.co.uk/news/20583036.warning-commuters-brighton-trains-start-later-tomorrow/?ref=rss Warning to Brighton commuters that trains will be later tomorrow