The fiasco, described by the company as an “operating incident”, left passengers locked in carriages while a taxi was summoned to pick up the guard.
There were long delays for commuters travelling on following services between Ilkley, Leeds and Bradford as a result.
The guard was left behind at Burley in Wharfedale, near Ilkley, causing one of the busiest services of the morning, from Ilkley to Leeds, to be terminated at Menston, half way down the line.
Passengers contacted The Yorkshire Post and took to Twitter to vent their frustration.
Commuter Martin Grund wrote: “Left locked in for 20 mins and now stuck at Menston. Awful comms and service.”
Another added simply: “Muppets!”
Last week’s survey on satisfaction among train commuters revealed that well under half of Northern passengers believed the company dealt well with delays - a figure lower than the previous year.
This morning’s delays were compounded by a train fault which caused cancellations on the Skipton line.
The requirement of trains to have guards to open and close doors is the cause of the long-running industrial dispute that has decimated train services in the south of England. Unions insist their continued employment is necessary for safety reasons.
The Ilkley train line, meanwhile, has been hit by a spate of train breakdowns during the winter.
Northern Rail confirmed that a guard had been left on a platform. A spokesman said: “As a result, the service was terminated at Menston station.”
The company said it was “currently investigating the cause of the incident” and insisted it would be “inappropriate to comment further until that investigation has taken place.”