STORY: Unions formed picket lines around rail stations for the second day this week and warned of more industrial action unless a deal can be reached to improve pay and avoid redundancies.
In London, the roads were busy as normally packed train platforms were empty, with trains parked on the tracks.
A spike in the cost of food and fuel is pushing many household budgets to the brink and is driving trade unions to demand higher pay increases for their members. The government has urged wage restraint to avoid an inflationary spiral.
Although talks are ongoing, a third day of strikes is planned for Saturday (June 25). Other industries are also moving towards industrial action in what unions say could be a "summer of discontent".
The government has criticised the strikes, calling them counterproductive and most damaging for those on low incomes who depend on public transport and are unable to work from home.
Later on Thursday, ministers will set out planned changes to a law that would make it easier for businesses to use temporary staff, in a moved designed to minimise the impact of strike action.