Thousands of commuters face severe disruption as the Easter getaway begins while a 24-hour strike by train guards continues.
A total of 12 companies are affected
The third one-day strike by members of the biggest rail union the RMT in a dispute over safety is affecting 12 rail companies.
Worst hit are Wales & Borders, Central Trains and Wessex Trains but other companies are operating almost normally.
The strike comes as the first of an estimated 1.8 million people travelling abroad for Easter began to leave from airports and seaports on Thursday.
Those staying in the UK were told to expect heavy traffic on major routes on Good Friday.
But AA Roadwatch said the rail strike had not led to extra traffic jams on the road.
A spokesman said: "The stoppage pushed a few more cars on to the roads, but with the schools
having broken up and with some people taking the day off as the weather was so good, it was not really that busy."
But he said he expected more motorists to be on the move on Friday.
Further travel disruption is expected as Paddington Station in west London is due to be closed over Easter while signalling work is carried out.
The closure means Paddington's Heathrow Express train service will not be operating.
On Thursday an RMT spokesman said: "Support for the strike is solid.
"Companies could be operating more services because they have had more time to train managers to take over the guards' role."
The RMT executive is expected to meet next week to consider more strikes.
The dispute centres on a change to the safety "rule book" whereby the driver now protects the train while the guard is responsible for passenger safety.
Previously both driver and guard were responsible for putting warnings on the line if there was a breakdown or accident.
Train companies affected (selection)
Arriva Trains Merseyside expected 50% service
Central Trains 23%
Connex South Eastern 75%
South Central 75%
Thames Trains 100%
Virgin West Coast 80%
Ken Usher, Midlands regional organiser for the RMT, told the BBC: "Health and safety is of paramount importance to us.
"We are not striking for better pay and conditions."
On the Virgin West Coast line 80% of trains are running with about 70% of services operating on the Connex South Eastern routes in south-east England.
Long-distance operators Midland Mainline are also among the train companies offering reduced timetables.
Silverlink, which runs services north west of London and up to the Midlands,
is running 422 out of its normal 601 trains.
Rail bosses are furious at the strike action with Scotrail boss Peter Cotton saying it was a "needless, pointless dispute" about safety rules.
But the RMT says there is no reason why the train companies cannot agree with the union on a joint approach to the safety role of guards.
Train companies not affected (selection)
Arriva Trains Northern
South West Trains
The RMT also has safety concerns about the use of management to "strike bust" by taking over for guards during strikes.
The Association of Train Operating Companies criticised the timing of the strike to coincide with the busy Easter getaway.
Meanwhile holidaymakers have started to head abroad despite sunshine and blue skies in the UK.
On Thursday temperatures reached as high as 24C (75F) although forecasters warned the mini heatwave would not last throughout Easter.
The Association of British Travel Agents said Spain and its islands were popular spots for Britons travelling abroad.
But UK tourist chiefs said around 2.6 million Britons were expected to take trips of one night or more in
England over Easter, spending £400m.