Only a fifth of services will run and half of lines will close as 40,000 members of the Rail, Maritime and Transport (RMT) union at Network Rail and 13 train operators walk out for the third day this week.
However, train companies and unions are edging closer towards a deal, senior rail sources said.
Bosses at Network Rail hinted last night that they had put together a package that meets one of the RMT’s key demands to end strike action.
The state-owned company had previously refused to rule out compulsory redundancies as part of efficiency savings that it was demanding in return for an improved pay offer.
But any breakthrough will be too late to halt today’s action.
It means several seaside resorts will have no services, including Bournemouth, Blackpool, Margate, Llandudno and Skegness. Cornwall will have no trains either.
Operators are telling passengers they should “only travel by train if necessary” and to check their journey in advance.
A source said that while stations were “relatively quiet” during the weekday strikes, with many commuters working from home, there was “a nervousness” about what will happen today.
Steve Montgomery, who chairs the Rail Delivery Group, which represents operators, said yesterday: “We are very disappointed that the RMT leadership has decided to continue with tomorrow’s strike, and the union leadership has chosen to take action which will severely inconvenience the millions of people who had plans over the weekend.”
“While we are doing our best to minimise disruption to passengers, our advice is to only travel if it is necessary. And if you are going to travel, please plan ahead.”
Passengers with pre-booked tickets for today can travel tomorrow or Monday instead, or claim a refund.
Yesterday, services reeled from a knock-on impact of Thursday’s strike because signallers and control room staff declined to turn up for overnight shifts.
RMT leader Mick Lynch claimed its members were “standing up for all working people trying to get a pay rise and some job security”.