A drive to increase passenger numbers on the new rail service between Bradford and London has been hindered by mechanical problems with one of the trains that runs on the route.

Grand Central, which runs three return services a day from the Interchange to London Kings Cross, reported a steady growth in passenger numbers for the first month after the launch of its ‘West Riding’ service on May 23.

But problems with the carburettor on a class 180 diesel train led to one of its three daily services being cancelled for three days in late June.

A spokesman for Grand Central said the “temporary blip” had caused the steady growth in passenger numbers to stall.

The spokesman said: “Passenger loadings had grown to about 300 a day by the eighth week but the week where we lost one return train a day knocked us back to about 200 a day.

“Numbers have now recovered but we are keen to give it that little extra push.

“The figures we are already achieving on the West Riding route took us about eight months to achieve on the North Eastern route.

“The North Eastern now regularly records over 11,000 passengers a week after two years’ operation.”

Now Grand Central has launched a ‘Summer Sizzler’ offer to entice more passengers onto the service.

Summer promotional fares on the West Riding route include a 50 per cent discount on single fares to London until August 20 for tickets booked online before July 30.

The spokesman said: “The disruption a couple of weeks ago caused the growth in loadings to plateau.

“Now it’s time to stimulate a bit of interest in the service, especially with the school holidays coming up. We want to attract as many people as possible.

“By way of comparison, we are where the Sunderland service was after about eight months, so it’s coming on.

“But we want to get the loadings up as quickly as possible and temporary blips don’t help.”