different plane from the lower glazing, with an intervening transom, and the steel panels were recessed on either side of each window opening to accommodate the difference between the flat glass and the curved sides. The opening portion of the windows were provided with sliding ventilators, with an external aerofoil for draught-free ventilation, the correct opening position being marked by a pair of arrows. Doors were provided with frameless droplights manufactured by Beclawat; these were supported by a spring-loaded lazytongs mechanism inside the lower part of the door, and the top of the window had a sprung metal clip engaging in slots on either side of the window opening. The original vehicles had timber veneer interior finishes, and on the main line vehicles small plastic labels were fixed to the panels, giving the type of wood and its country of origin e.g. "Crown Elm Great Britain"; "Lacewood Great Britain", etc. In 1955, an order was placed for 14 vehicles, with manufacturers being invited to incorporate innovative features; perhaps the most striking of these prototypes, which were completed in 1957, were those constructed by Cravens. Following evaluation, and with the increasing influence of the British Transport Design Panel, Mark 1 vehicles built from the later 1950s onwards were to modified designs. Laminates were used instead of timber panelling, and in the last of the Mark 1 hauled vehicles, fluorescent lighting was fitted instead of tungsten bulbs. An important variant on the Mark 1 design were the 44 Pullman vehicles built by Metro-Cammell in 1960. A further change introduced in the late 1950s was the use of aluminium window frames instead of direct glazing into the steel panelling. The underframes consisted of a heavy assembly of steel sections, with angle used to form bracing trusses. These were placed close to the centre line of the vehicle rather than beneath the solebars, as was characteristic of previous vehicles. The original bogies were a double bolster type, which like the carriages mounted upon them, were designated "BR Mark 1" (BR1 for short). These proved unsatisfactory and a new cast-steel design was introduced from 1958 (often referred to as the Commonwealth type). This gave a superb ride with minimal tyre wear, but was heavy. The final batches of locomotive hauled Mark 1s, and many Mark 1 EMU vehicles, were built with the Swindon-designed B4 bogie. Later on, many BR1 bogie vehicles were retrofitted with the