Avanti West Coast has told passengers that most of its network will have no services, and is advising them not to travel. Hull Trains will only run one service from London King's Cross.
LNER said it will only run an extremely limited timetable and its trains will be very busy. There will only be one return train from Leeds to London all day, and one train every two hours in both directions between Edinburgh and London.
Greater Anglia has told passengers not to travel on Saturday because of the reduced service, with no direct trains on that route. There will be no direct Stansted Express trains on Sunday.
The London Underground is expected to be affected. Transport for London has advised passengers that there will be no service on the entire London Overground network, operated by Arriva Rail London, whose drivers are part of the strike.
The Rail Delivery Group, which represents train operators, said passengers with tickets on the strike day can use their ticket on the day before, or up to and including Tuesday 16 August.
In 2021, the median salary for train and tram drivers was 59,189 per year, while other rail workers such as ticket collectors and guards get 33,310. The lay and repair workers who lay and repair tracks receive 34,998 on average.
Train drivers union Aslef wants a pay rise for its members to reflect the increased cost of living. Train companies say they want to give a pay rise, but reforms are required to fund it. There isn't a deal yet.
The RMT union, which represents guards and signalling staff, has held talks with Network Rail, which owns the UK's railway infrastructure, but again a pay deal is yet to be agreed, with wage rises below the current inflation rate.
The government said the railway system needs modernisation and has to be financially sustainable for the long term. It says 16 billion of taxpayers' money was used to support the railways during the Covid epidemic. It says changes are needed, with passenger numbers still down by one-fifth.