Tragedies like the Potters Bar train crash will reoccur if proposed cost-cutting measures are introduced on the railways, unions warned before the 10th anniversary of the disaster.
The Government is considering a Department for Transport-ordered report containing a number of options for cash-cutting across the UK rail network.
But transport unions say that if recommendations made in Sir Roy McNulty's review are implemented, they would spell the break-up of Network Rail and an end of its not-for-dividend status.
The result, they say, would be profit being put before safety.
This Thursday's anniversary of the Hertfordshire crash that claimed seven lives should serve as a "wake-up call" to ministers, the Rail, Maritime and Transport (RMT) union said.
More deaths are "inevitable" if cost cuts lead to repairs and maintenance being scaled back, boss Bob Crow argued.
He said: "Once again rail services are going to be run for profit, setting up the same poisonous set of conditions that led to problems in the past.
"If profits are the motive then repairs and maintenance work doesn't get done because people want to maximise returns for shareholders. This is what happened in the run-up to previous tragedies.
"Though they're not going for full-scale privatisation of Network Rail, they're talking about alliances where effectively the train-operating companies are calling the shots.
"We think the result will be further unnecessary deaths and injuries on the railways.
"The anniversary of the Potters Bar crash is a wake-up call 10 years on for the Government to look again and realise this is not the way to run a railway."
The report says it is "vitally important" that infrastructure managers and train operators have a "commercial interest in each other's costs and revenues".
One way of doing this would be through joint ventures or alliances between Network Rail and train operators, it suggests.
Simon Weller, national organiser of train drivers' union Aslef, said: "The system failures from Potters Bar are now being reintroduced into the rail industry by driving costs down and outsourcing work.
"This is how we ended up in the whole Potters Bar mess. We'll probably see more Potters Bars because the profit motive has been reintroduced into track, signalling and infrastructure work.
"Cutting corners with safety to keep costs down is likely."
But the government stressed that it took rail safety "very seriously".
Transport Minister Theresa Villiers said: "Our railways are as safe as they have ever been and the Government is clear that this good record needs to continue.
"The Office of Railway Regulation has a defined role in scrutinising the work Network Rail does to ensure passenger safety and both the regulator and the government take rail safety very seriously.
"It is vital that we reform the industry and drive down costs to get the more efficient service passengers and taxpayers deserve.
"Eliminating waste and inefficiency through smarter working can be done without jeopardising safety."
The government is expected to announce its decisions on the McNulty review later this year.
Six passengers on the West Anglia Great Northern express - Austen Kark, Emma Knights, Jonael Schickler, Alexander Ogunwusi, Chia Hsin Lin and Chia Chin Wu - were killed in the Potters Bar crash.
They were in the train's fourth carriage, which became airborne after derailing and ended up getting wedged under the canopy of the station.
A seventh victim, Agnes Quinlivan, 80, was killed by falling debris as she walked close to Potters Bar station.
Network Rail admitted failings over the installation, maintenance and inspection of adjustable stretcher bars which keep a moveable section of a track at the correct width for train wheels.
It was fined £3 million last May, having pleaded guilty at St Albans Crown Court in Hertfordshire to breaching health and safety regulations
Mr Kark's wife, author Nina Bawden, 87, was badly injured in the crash.
She said of her late husband: "I think about him all the time."
But she was confident safety had improved in the past decade.
"I think they've done quite a lot since then," she said.
Memorial services to commemorate the disaster will be held on Thursday, including one at the memorial garden outside Potters Bar station and one at the local church of Our Lady and St Vincent.
Flowers will be laid and a minute's silence will be held at the memorial garden at 12:56pm, the time the train crashed.