RMT general secretary Mick Lynch said the offer does not meet criteria for securing a long-term settlement on job security, a decent pay rise and protecting working conditions for staff.
The RMT has rejected an offer from train operators aimed at preventing strikes over the Christmas period, the union has announced.
The Rail Delivery Group (RDG) said its proposed framework would have supported pay increases of up to 8%, covering 2022 and 2023 pay awards, while delivering much-needed reforms.
But the RMT, led by secretary general Mick Lynch, has turned it down.
The union said: "The RDG is offering 4% in 2022 and 2023 which is conditional on RMT members accepting vast changes to working practices, huge job losses, Driver Only Operated (DOO) trains on all companies and the closure of all ticket offices."
Mr Lynch added: "We have rejected this offer as it does not meet any of our criteria for securing a settlement on long term job security, a decent pay rise and protecting working conditions.
"The RDG and Department for Transport (DfT), who sets their mandate, both knew this offer would not be acceptable to RMT members.
"If this plan was implemented, it would not only mean the loss of thousands of jobs but the use of unsafe practices such as DOO and would leave our railways chronically understaffed."
RMT has demanded an urgent meeting with RDG on Monday morning in the hope of trying to resolve the dispute, the union posted on Twitter.
In a statement posted on the RMT website, Mr Lynch said the talks would aim to secure "a negotiated settlement on job security, working conditions and pay."
It means rail strikes planned during December and early January are still scheduled to go ahead, with commuters facing severe disruption on 11, 12, 13, 14, 16, 17 December, and 3, 4, 6 and 7 January.
The RDG said it was proposing a "fair and affordable offer in challenging times, providing a significant uplift in salary for staff" which would deliver "vital and long overdue" changes to working arrangements.
The draft framework agreement gives RMT the chance to call off its planned action and put the offer to its membership, a statement said.
"If approved by the RMT, implementation could be fast-tracked to ensure staff go into Christmas secure in the knowledge they will receive this enhanced pay award early in the New Year, alongside a guarantee of job security until April 2024," an RDG spokesperson said.
"With revenue stuck at 20% below pre-pandemic levels and many working practices unchanged in decades, taxpayers who have contributed £1,800 per household to keep the railway running in recent years will balk at continuing to pump billions of pounds a year into an industry that desperately needs to move forward with long-overdue reforms and that alienates potential customers with sustained industrial action."
The company called on the union to "move forward with us" so we can "give our people a pay rise and deliver an improved railway with a sustainable, long-term future for those who work on it."
Transport Secretary Mark Harper described the situation as "incredibly disappointing and unfair to the public, passengers and rail workforce who want a deal".
The deal will "help get trains running on time", he said.
A bleak winter of strikes
Motorists have also been warned to brace for Christmas chaos after road workers revealed they will down tools for 12 days to coincide with rail walkouts.
National Highways workers, who operate and maintain roads in England, will take part in a series of staggered strikes from 16 December to 7 January, the PCS union said.
A growing list of unions are threatening to grind the country to a halt, putting pressure on Prime Minister Rishi Sunak.
He is attempting a more constructive, less combative approach with the unions as the government treads a careful line between "being tough but also being human - and treating people with respect", a government source told Sky News.
Some 10,000 paramedics voted to strike in England and Wales, the GMB union announced this week.
They join up to 100,000 nurses set to walk out in the biggest-ever strike by the Royal College of Nursing (RCN) in England, Wales, and Northern Ireland on 15 and 20 December.
On Sunday morning, Conservative Party Chairman Nadhim Zahawi told Sky News' Sophie Ridge on Sunday the army could be deployed to help ease possible strike disruption over Christmas.