Commuters, disability campaigners and politicians are to join union leaders at a protest to mark the second anniversary of the bitter disputes over the role of train guards.
The Rail, Maritime and Transport union (RMT) is organising the event in Westminster on Wednesday, marking two years since the row started on Southern Railway.
The dispute has spread to four other train operators - South Western Railway, Merseyrail, Arriva Rail North and Greater Anglia.
A series of strikes have been held, with the next walkout due on May 5 against Greater Anglia.
RMT general secretary Mick Cash said: "The sheer grit and determination of our members to put public safety before private profit over the past two years is a credit to the trade union movement and the communities they are standing up for.
"We will be demonstrating outside Parliament to show that we are as determined now as we were two years ago to defend the role of the guard on the train and the basic principles of passenger safety and accessibility.
"RMT has successfully secured agreements in both Wales and Scotland that lock in the guard guarantee and, if it's good enough for Wales and Scotland to put safety and the role of the guard centre-stage, then it should be good enough for the rest of Britain as well."
Rail users from groups including the Association of British Commuters will join the protest, as well as politicians and disabled passengers.
Andy Bindon, human resources director at Govia Thameslink Railway, parent company of Southern, said: "We urge the RMT to finally bring to an end this pointless industrial action.
"The changes they are objecting to were introduced on Southern more than 15 months ago, and their members have been working in the more passenger-focused role ever since, resulting in a more efficient service with more on-board staff and fewer cancelled trains.
"Southern ran a normal service on most of its routes on the last day of action, with 95% of trains in the strike-day timetable and the vast majority of employees coming to work.
"The RMT has staged 40 days of strikes on a mandate that is more than two years old and we have made numerous offers to them - none of which have been put to their members."
The RMT said there were persistent rumours in the rail industry that a number of train operators were facing financial difficulties.
Unions have been pressing Transport Secretary Chris Grayling to bring the East Coast franchise back into public control after Stagecoach and Virgin were told they could exit the franchise three years early because of losses.
Mick Cash said: "The game is up for the Tory Government. It is now no longer a question of if Britain's railways are taken back ?into public ownership - it's a question of when.
"It is frankly scandalous that a huge chunk of Britain's private rail operations ?now stand on the brink of collapse due to the gross mismanagement of the train companies in cahoots with Chris Grayling and his Government."