Launched on Tuesday, the train operator put up three million tickets on sale at a price of just £2 for adults and £1 for children. READ MORE: Northern launches £2 tickets sale to all these destinationsNorthern trains is looking to recruit engineering apprenticesAlex Hornby, commercial and customer director for Northern, said: "We are just 24 hours in and the response has been incredible. Northern's Flash Sale is always very popular, but this one is shaping up to be one of the busiest yet. Tickets are available to buy on Northern's app, online, and at ticket offices and on ticket machines at stations managed by Northern. Tickets are valid for travel between Monday, October 6, and Friday, October 24.