Jeremy Corbyn has insisted train companies need to be put under public ownership as soon as possible as Labour launched a Rail Mayhem campaign day.
Commuters across the country are being targeted by activists on the first working day that the East Coast mainline comes back under public control.
Trains on the route between London and Scotland are being run by the Department for Transport's (DfT) Operator of Last Resort, branded as
London North Eastern Railway (LNER), following the failure of the Virgin Trains East Coast (VTEC) franchise.
Speaking after handing out leaflets at London's King's Cross station, Mr Corbyn said the rail system needed change.
"We need it publicly owned and under public control, and we need it as quickly as possible.
"It really is time that we the public owned and ran the railways.
"We pay for the infrastructure, we do the investment, we own an awful lot of it, we should own the whole lot."
Andy McDonald, Labour's shadow transport secretary, repeated calls for Transport Secretary Chris Grayling to quit.
He said: "The rail mayhem that we've seen on our railways was caused by one man and that man is Chris Grayling.
"Passengers across the country are right to be angry at the way he has handled the latest in a long run of rail fiascos.
"Chris Grayling has lost all credibility and it's time for him to go."
The campaign day sees more than 200 events take place to leaflet commuters.