A fresh strike by rail workers will go ahead on Thursday after talks failed to find a breakthrough.
It comes on a day around 60% of services ran despite no strike action on Wednesday - as it took time for trains and crews to get to depots following Tuesday's walkout.
Some services will start to run down on Wednesday evening, with Thursday promising the kind of chaos Tuesday brought for commuters.
Around 20% of services will run and just half of lines will be open - only between 7.30am and 6.30pm.
Here's a look at how each rail operator's services will be impacted on Thursday and what you can do if you're worried about losing money or time at work.
Avanti West Coast
A limited service of around a quarter of the normal timetable will operate, and only between 8am and 6pm.
A number of routes will not be served, such as to North Wales, Stoke and Edinburgh.
The operator has already suspended ticket sales for travel between Tuesday and Sunday to “help reduce disruption and overcrowding.”
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It will operate fewer than a third of normal services, only between 7.30am and 6.30pm.
This will include two trains per hour from London Fenchurch Street to Shoeburyness via Laindon, and the same frequency from London Fenchurch Street to Pitsea via Rainham.
No trains will run via Ockendon or Chafford Hundred.
Services will be suspended on “most routes” on strike days due to “extremely limited availability of staff.”
Cross Country Trains
No services will run from Birmingham New Street to Bristol Temple Meads, Cardiff Central, Peterborough, Cambridge or Stansted Airport.
A “very limited service” is planned between Bristol Parkway and Plymouth, and Birmingham New Street and Edinburgh Waverley via Leeds, York and Newcastle.
There will also be a reduced service between Birmingham New Street and Manchester Piccadilly.
East Midlands Railway
Services will be reduced between Tuesday and Sunday, with just one train per hour running in each direction on most routes.
Great Western Railway
A number of services will not be running, including all those in Cornwall and Devon and on the South Wales main line, Heart of Wessex line, Severn Beach line, North Cotswolds line and South Cotswolds line.
More than half the planned trains from London to Castle Cary between Wednesday and Friday have been cancelled.
Most stations and routes will be closed on strike days, and a “severely reduced service” will operate elsewhere.
There will be no services to or from London Victoria or Charing Cross.
The vast majority of its network in Kent and East Sussex will be closed, apart from the high-speed route to Ashford International.
The firm will not run any trains on its regional and branch lines.
A “very limited service” will operate on some routes to and from London Liverpool Street.
London North Eastern Railway
Around 38% of usual service levels are planned, but trains that do run “are likely to be very busy.”
Meanwhile, members of the drivers’ union Aslef on Greater Anglia will also strike on Thursday in a separate dispute over pay.
London Northwestern Railway
Services will be “very limited.”
This includes just two trains per hour between London Euston and Northampton, and one per hour between Birmingham New Street and Northampton.
No trains will operate between London Euston and Crewe.
The last train from London King’s Cross to Edinburgh will be at 2pm, while the final service to Leeds will depart at 3.05pm.
Passengers are urged “not to travel” as services will be suspended “on most routes.”
No trains will run north of Glasgow or Edinburgh on strike days. Just two trains per hour will run between the cities via Falkirk.
South Western Railway
A “severely limited service” will run between 7.15am and 6.30pm, and only on some routes.
This includes only four trains per hour between London Waterloo and Woking, and two per hour between London Waterloo and Basingstoke.
There will be a “significant reduction in available services.” Several stations will be closed, such as Middlesbrough, Scarborough and Selby.
Transport for Wales
Most lines will be closed on strike days.
A reduced service will run between Radyr and Treherbert, Aberdare and Merthyr Tydfil, with replacement bus services between Radyr and Cardiff Central on Thursday.
West Midlands Railway
The industrial action will have a “considerable impact on the number of trains” that run on Thursday.
No trains will run on several routes to and from Birmingham New Street, such as Hereford, Shrewsbury, Walsall.
Will the Tube be closed again too?
No, Transport for London will run a service across the majority of its lines but disruption is expected to continue on Thursday.
There will a reduced service on the London Overground and Elizabeth line (where TfL uses national rail assets).
Helicopter footage from across London showed empty platforms and lines of trains not in use on Tuesday
London Overground services will run a reduced service from 7.30am and passengers are advised to complete their journey by 6pm.
On the Bakerloo line, there will be some disruption to trains from Queens Park to Harrow and Wealdstone , while the District line is only operating from 7.30am to 6.30pm on the Richmond and Wimbledon branches.
What about services to airports?
Many of the operators above normally offer regular trains to the UK's various airports. If you have a flight to catch, it's best to check directly with the train operator.
Here's a look a few of the services affected:
Stansted Express : a reduced frequency will be in place, with later first trains and earlier last trains. No services will run from Stansted Airport to Norwich and Cambridge.
Heathrow Express : services will be “significantly affected” this week, with a half hourly timetable between 7.30am and 6.30pm on strike days.
Gatwick Express : there will be no service on Thursday. Passengers travelling to Gatwick Airport from London can use Southern or Thameslink trains.
Manchester Airport : from Manchester Piccadilly, there is generally one train an hour leaving to Manchester Airport, with the last service running at 5.31pm.
What rights do I have with my employer if I'm unable to make it back in time for work?
If an employee cannot get to work or is going to arrive late because of bad weather or transport problems, employment advisory body ACAS advises that they should tell their employer as soon as possible.
"Employees don’t have a legal right to be paid for working time they’ve missed due to travel disruption," Gary Wedderburn, Senior Advisor at ACAS explained.
"It is a good idea for employers and employees to discuss and agree how any missing time will be treated."
For example, taking extra days as holiday, unpaid leave or paid special leave.
He added: “Different workplaces will have different policies, so it is always a good idea to check at the earliest opportunity.”
So can passengers claim compensation?
It can be complicated.
It’s best to check with specific operators and services to see if they are running an emergency timetable.
This is important as you can only claim compensation during a rail strike for a delay based on the replacement or emergency timetable for train or replacement bus services, according to consumer group, Which?
Even then, you could only be eligible for compensation once you’ve boarded an alternative service and it’s delayed.
But the length of the delay you have to endure before you get offered a payout can vary from company to company.
Transport Secretary Grant Shapps said season ticket holders would be paid “full compensation on strike days” and he had “moved to help make that an automatic process.”