 However, Ashford works was heavily engaged in tackling a backlog of repair and maintenance work caused by government restrictions during the First World War with little spare capacity for new construction projects, particularly when approval for the construction of the N1 prototype coincided with a priority order for 15 2-cylinder N class locomotives.In consequence, the works backlog meant that only 12 N class locomotives were completed between June 1920 and October 1922.Seeing little sign of an increase in production capacity at Ashford, Maunsell decided to construct the prototype N1 locomotive from parts intended for use on the next N class locomotive in the batch, No.