Thousands of passengers have joined a campaign for more train services from Yorkshire to London, according to the rail operator GNER.
GNER says it needs extra services as part of its franchise agreement
The Office of Rail Regulation (ORR) is proposing to reject GNER's bid for more East Coast Mainline trains saying the route cannot cope with extra traffic.
But GNER claims more than 5,000 people have contacted the ORR in less than a week, supporting the extra services.
The ORR said it wanted to hear public views before making a final decision.
The refusal of GNER's application is due in part to the ORR's draft approval of plans for a new company to run trains from Yorkshire to London.
Grand Central wants to run three daily direct services on the East Coast Main Line in competition with GNER.
The trains would travel from Bradford, Halifax and York and be run without public money.
In January, the ORR said it was minded to approve Grand Central's plans but it would mean GNER's application and another from Grand Central for extra services to Bradford would be rejected.
But GNER argues it needs the extra capacity to run more services promised in its franchise agreement last year.
Members of the public have until 13 February to voice their opinions on the ORR's draft decision.