Train firms were accused of launching a “savage attack” on rail workers and passengers with proposals to close up to 1,000 ticket offices across England.
The Rail Delivery Group (RDG), which represents train companies, confirmed plans that could result in the mass axing of offices over the next three years.
Bosses insisted it needed to “modernise”, with staff moved from behind counters to platforms and elsewhere.
It wants more passengers to use self-service ticket vending machines instead.
The RMT claimed operators had already issued hundreds of redundancy notices.
Mick Lynch, the union’s general secretary, said: “The decision to close up to 1,000 ticket offices and to issue hundreds of redundancy notices to staff is a savage attack on railway workers, their families and the travelling public.
“Travellers will be forced to rely on apps and remote mobile teams to be available to assist them rather than having trained staff on platforms.
“This is catastrophic for elderly, disabled and vulnerable passengers trying to access the rail network.”
Ticket counters will remain at the busiest stations.
In others, ticket office staff will be offered the chance to take up what the RDG called “multi-skilled customer help roles”.
It argued the proportion of tickets bought over the counter has fallen from 82% in the mid-1990s to 12% now.
The RDG also denied that the proposals could lead to more crime at stations, with the RMT branding the shake-up a “muggers’ paradise”.
It cited analysis of British Transport Police figures that showed crime decreased in the six months after Transport for London moved staff out from Tube ticket offices in 2015.
Jacqueline Starr, Rail Delivery Group chief executive, said: “The ways our customers buy tickets has changed and it’s time for the railway to change with them.”
A three-week consultation on closures will be overseen by Transport Focus and London TravelWatch, which represents passengers.
The closures will be phased over the next three years.
Peter Pendle, interim general secretary of the TSSA rail union, said the government would “soon realise that the public have no desire to see their rail network diminished in this way”.
Vivienne Francis from the Royal National Institute of Blind People (RNIB), said: “A mass closure of rail ticket offices would have a hugely detrimental impact on blind and partially-sighted people’s ability to buy tickets, arrange assistance and, critically, travel independently.”
Only 3% of people with sight loss can use a ticket vending machine without problems, she said.
Labour's shadow transport secretary Louise Haigh urged the Government to "come clean" over ticket office closures.
She said: "Despite the concerns of vulnerable passengers, Conservative ministers are ducking and diving from scrutiny.
"They refuse to say how many stations have alternatives to ticket offices, what the impact will be on jobs, or how it will hit vulnerable rail users.
"The Conservatives should come clean and give passengers the answers they deserve.
"Railroading this decision in just three weeks, without proper consideration for staff and vulnerable passengers, only risks exacerbating the managed decline of the rail network."
