The new travel restrictions mean that rail services are likely to be halved.
This week, people were instructed to stay at home, work from home where possible and not do any non-essential travel.
One the tube during peak hours on Tuesday, usage was just 18% of pre-pandemic levels.
The Department for Transport said: “We will work with operators in the coming days to assess the right level of service provision as we have done throughout the pandemic.
“While we cannot predict the long-term effect of Covid-19 on travel patterns, it is critical that we ensure the railway can respond quickly to changes in passenger demand whilst supporting economic recovery.”
Robert Nisbet is a director of industry body the Rail Delivery Group. He said: “We are working closely with the government to ensure we run the right level of services … By increasing cleaning and providing better customer information, our people are ensuring that those who must travel can do so with confidence.”
Flights are also likely to cut and holiday firms are cancelling holidays under the new rules.
A BA spokesperson said: “Our focus is on keeping crucial air links open – transporting vital goods and ensuring people who are permitted to travel can continue to do so safely.”
EasyJet said that it would reduce domestic and international flights and customers unable to travel would be offered a refund or chance to rebook. The airline has called on the government to increase its support to the sector, saying “such as has been provided to hospitality, where decisions have directly affected the ability to trade. The same principle should be applied to aviation.”