Following the second of three days of planned strike action by members of the Rail, Maritime and Transport (RMT) union, Friday (24 June) will also see mass disruption on the network, despite no strike action taking place.
Fewer than one in five trains ran on Tuesday and Thursday after members of the RMT on Network Rail (NR) and 13 train operators staged the first of three walkouts, with a third round of strikes set to follow on Saturday.
But despite Friday not being a day of strike action, there will be continued disruption to services, train operators have warned.
Here is everything you need to know about it.
Which services are running?
As people once again shifted to using vehicles or buses to get to work in place of the trains, the second day of rail strikes caused travel chaos throughout the UK, resulting in lengthier journey times and congested roads.
Only around 60% of the 20,000 normal weekday services will be able to operate on Friday, which will see continued disruption.
Some operators will also wind down services slightly earlier than normal tonight ahead of Saturday’s walkouts.
Walkouts by signallers and control room staff who would usually have worked overnight from Thursday night into Friday morning meant trains left depots later than normal, delaying the start of services.
Trains normally leave depots between around 3am and 4am, and passenger services usually begin between around 5am and 6am.
But the process of taking trains out of depots could only begin on Friday when signallers on daytime shifts started work at 6am - 6.30am.
Network Rail said that “even during the day the service will stay thinner” than usual and some operators will wind down services slightly earlier than normal.
How severe will delays be?
In London and other major cities, service frequencies are expected to increase relatively quickly, as trains do not have to travel long distances from depots to stations.
But in more remote locations, it could take several hours for timetables to resemble their usual schedules.
The start of services is thought to have been delayed by up to four hours on some lines.
In Scotland, ScotRail said while large signalling centres at Yoker, West of Scotland and Edinburgh will be able to operate from 7.15am, this will not be the case at manual boxes elsewhere, and it may well be early afternoon before many routes are able to operate as normal.
What’s the picture on Saturday?
Saturday (24 June) sees the return to strike action for RMT members, and so rail services will once again be adversely affected.
Around 20% of services will run and just half of lines will be open, and only between 7.30am and 6.30pm.
Could the strikes be called off?
Talks to this point have been unsuccessful in reaching an agreement between the RMT, National Rail and the train companies, so the remaining day of strike action being called off seems unlikely at this point.
Passengers are urged to check with train operators for updates to services.
The third strike of the week is planned for Saturday (25 June).
Why are they striking?
RMT general secretary Mick Lynch said the turnout at picket lines on Tuesday was “fantastic” and had exceeded expectations in the union’s campaign for job security, defending conditions and a decent pay rise.
He said: “Our members will continue the campaign and have shown outstanding unity in the pursuit of a settlement to this dispute.
“Now is the time to stand up and fight for every single railway worker in this dispute that we will win.”
According to a poll, the majority of adults are in favour of the rail strikes.
58% of respondents to a Savanta ComRes survey of more than 2,300 people believed the industrial action was justified.
Lynch added: “RMT members are leading the way for all workers in this country who are sick and tired of having their pay and conditions slashed by a mixture of big business profits and Government policy.”