The late 1930s saw the era of the classic coach design, with operators becoming increasingly conscious of the appearance of their coaches. Many coach bodies were of individual design, but readily identifiable as Duple. The introduction of sloping pillars, curving roof- and waist-lines along with shaped mouldings on the side panels all contributed to a new 'aerodynamic' style that was increasing in popularity. Although coachwork continued to be Duple's main product, single-deck bus bodies formed a good part of the production from the mid-1930s, with one customer, Barton Transport, placing a bulk order for such bodies to be delivered over an extended period.