The extent of overcrowding and delays on Britain's rail network has been highlighted by a new survey.
More than half of travellers (53%) could not get a seat at least once during the past six months, while one in seven (15%) said this occurs "regularly", according to the poll by consumer group Which?
Some 12% of passengers experience frequent delays, while half reported being in a carriage that was dirty or contained litter.
Which? said it has been contacted by thousands of people sharing details of their nightmare train journeys.
One passenger, Jerry, claimed "animals are treated better" as there is "mass overcrowding" and cancelled services, while another traveller, Phillip, said several complaints made by him and his wife have been ignored.
Which? is calling on the next government to "hold train companies to account" by establishing a statutory transport ombudsman that all operators must join, to help manage passenger grievances.
The watchdog's managing director of public markets, Alex Hayman, said: "The rail sector is failing passengers on too frequent a basis.
"People believe that improving rail services should be one of the top priorities for the next government, which isn't surprising given the numerous stories we have heard about constant delays and overcrowding that many people face on a daily basis.
"The next government will need to quickly step up and ensure that passengers are getting a much better standard of service.
"Trust can only begin to be restored by introducing an independent, statutory ombudsman, and a stronger regulator that stands up for passengers."
The research involved interviews with 880 people who had travelled by train in the previous six months.
A spokesman for the Rail Delivery Group, representing train operators, said: "Together the rail industry is investing, competing and innovating to improve as one team.
"Our promise is to deliver 6,400 extra services a day and 5,500 new carriages by 2021, part of a £50 billion-plus upgrade plan driving improvements for customers now and for the long-term - making every journey better as we build a faster and more reliable railway for Britain."
The latest survey of almost 30,000 passengers by Transport Focus in autumn last year revealed that just 81% were satisfied with the railways, a figure which has not been lower since spring 2007.
A draft version of Labour's manifesto leaked to national newspapers indicated that a government led by Jeremy Corbyn would renationalise the railways as each private franchise expires, with fares frozen and guards put back on driver-only trains.