A recovery operation is under way to clear and repair a busy passenger rail line after a freight train derailed.
Eleven carriages came off the tracks at Queen Adelaide near the Ely North junction, Cambridgeshire, on 14 August.
A rail crane has begun lifting the stricken wagons, with some individual sections weighing as much as 106 tonnes.
A spokesman for Network Rail said teams would work "day and night" to reopen the line by Monday.
The 33-carriage freight train had been travelling from Felixstowe to Doncaster when the accident happened at about 14:30 BST on Monday. No one was injured.
The line remains closed, affecting passenger services from Peterborough and Cambridge to Stansted Airport and London.
A quarter of a mile (400m) section of track will need to be replaced, according to Network Rail.
However, the company remains tight-lipped on the nature of the freight involved, or the speed of the train at the time.
Simon Ancona, Network Rail's chief operating officer for Anglia, said: "We have an army of experts and specialist teams who are working day and night to remove the wagons as quickly as possible.
"Once they are out of the way we can replace the tracks, carry out the necessary repairs, reopen the line and get passengers on the move again.
"We expect to be able to reopen the line on Monday. I'd like to thank passengers for their continued patience."
But Chris McRae, of the Freight Transport Association, said much of the freight involved would now have to travel by road, causing "problems in the logistics supply chain".
"It is easy to get passengers onto buses, you cannot get freight onto buses," he said.
"There's been a lot of Government investment in key strategic rail freight routes in terms of enhancing them to take more freight, bigger freight, longer freight trains and that's really important in terms of economic growth and connectivity.
"But what is equally important is diversionary capability - so that when something like this happens it means there is an alternative method - without having to replan it by road."