They were on platforms at stations along the line as part of the party’s ‘Keep the East Coast on Track’ campaign.
The Government is committed to finding a private company to run services on the intercity route linking Yorkshire to Scotland and London.
But Labour argues East Coast, a Government-backed business, has run the service successfully and there is no need for privatisation.
Wakefield MP Mary Creagh said: “Since being run on a not-for-private-profit basis, East Coast has done a terrific job for passengers travelling to and from Wakefield – it’s not broken so it doesn’t need fixing.
“What’s more, by the end of this financial year it will have paid £800m back to the taxpayer and reinvested a further £40m profit in the service – a stark contrast to the failed franchises we’ve seen in recent years.
“It makes no sense to go back to that failed model which saw two private operators fail mid-way through their contracts.
“From speaking to passengers today it’s clear they’re firmly on our side – not one person of the dozens we’ve spoken to thinks it should be reprivatised.”
East Coast has operated services on the line since 2009 when the previous franchise-holder, National Express, pulled out saying it could not afford to meet financial commitments it had made to the Government.
The current Government has announced plans to have the franchise back in the private sector by February 2015.