Train drivers at nine rail companies will strike on 13 August, the Aslef union has announced, as passengers faced further disruption today due to industrial action.
Only around one in five trains ran on Wednesday, on about half the network, with some areas having no trains all day.
Picket lines were mounted outside stations as members of the Rail, Maritime and Transport (RMT) union at Network Rail and 14 train operators went on strike.
The lack of rail services caused more people to head out on to the motorways - with average speeds on the M1 dropping as low as 14mph, according to traffic site Waze.
Trains will also be disrupted on Thursday morning with a later start to services as employees return to duties.
Thousands of drivers at nine rail companies are to stage a one-day strike on Saturday 13 August in the worsening pay dispute.
A separate walkout by drivers at seven rail operators is already planned for this Saturday.
Both strikes will affect Greater Anglia, Great Western Railway, Hull Trains, LNER, London Overground, Southeastern and West Midlands Trains.
Staff at Avanti West Coast and Cross Country will not take part on Saturday but have now decided to take industrial action in August.
Aslef said train companies had failed to make a pay offer that would keep pace with rising living costs.
The union said workers have not had a pay rise since 2019, which amounts to a real terms cut over the last three years when soaring inflation - set to hit 11% this autumn - is taken into account.
"We want an increase in line with the cost of living - we want to be able to buy, in 2022, what we could buy in 2021," said general secretary Mick Whelan.
"It's not unreasonable to ask your employer to make sure you're not worse off for three years in a row.
"Especially as the train companies are doing very nicely, thank you, out of Britain's railways - with handsome profits, dividends for shareholders, and big salaries for managers - and train drivers don't want to work longer for less."
Network Rail previously said it had offered workers a two-year 8% pay deal with a guarantee of no compulsory redundancies, and other benefits.
Train drivers at Chiltern, Northern and TransPennine Express have until 25 August to vote on further strike action, while those at East Midlands Railway have until 19 September.
Two further days of rail strikes have already been announced by the RMT for 18 and 20 August, while a Tube strike is set to affect London on 19 August.
A Rail Delivery Group spokesperson said: "The action announced by the Aslef leadership shows a cynical approach to talks, a total disregard for passengers and is putting everyone's summer plans at risk.
"This action will bring the total number of strike days on the railway to 10, disrupting plans in June, July and August.
"Like any public service we have to change with the times, and it's only by making necessary reforms that we can give our people a pay rise."
Earlier, a row broke out between unions and the Transport Secretary Grant Shapps after he laid out plans to curb industrial action, including stopping coordinated industrial action, limiting picketing and having a cooling off period after strikes.
He told the Daily Telegraph: "I'm looking at banning strikes by different unions in the same workplace within a set period.
"We should also place an absolute limit of six pickets at points of Critical National Infrastructure, irrespective of the number of unions involved, and outlaw intimidatory language.
Unite general secretary Sharon Graham said: "If Grant Shapps had his way we would all still be in the workhouse."
Unison general secretary Christina McAnea said: "The government wants to turn the clock back to Victorian times when children were sent up chimneys and working people ruthlessly exploited."