The East Coast rail service suffered falling revenues and made losses
Unions are being urged to back a motion to keep in public hands a rail franchise taken over by the government after the operator made big losses.
Rail union Aslef has started a campaign to keep the East Coast Main Line service permanently nationalised.
National Express decided to hand back a contract for services between London and Scotland when it failed convince ministers to revise its terms.
The union also now wants to nationalise the London to Norwich and Essex lines.
The franchise was taken away from National Express when the company made huge losses because of falling revenue and low passenger numbers.
The handover to the government officials who will run the franchise is expected in the next few weeks so technically it is still in private hands.
Remove other contracts
Delegates at the TUC's annual conference in Liverpool are to vote later on calls to keep the line in public hands after the transfer takes place.
Aslef has also tabled a motion urging ministers to abandon plans to find another buyer next year and run it instead on a not-for-profit basis.
It also urges the government to ban the bus company from ever running a rail service again.
In addition the union wants to remove the firm's remaining train contracts.
These are the National Express East Anglia routes through Cambridgeshire, Essex, Hertfordshire, Norfolk and Suffolk plus the C2C service between London and Essex.