The ‘Sunshine Stock’ (also known as ‘new type’) were introduced in 1936 and entered service on premier expresses such as The Bristolian and the Cheltenham Flyer. Subsequently they were cascaded into general service. The name derived from the large picture windows on the corridor side. They had end vestibules and a mix of window sizes with 4′ wide for 3rd class and 5′ wide for 1st class.
Slip coaches provided services to intermediate stations along the line without the need to stop the main train. At a pre-arranged location the guard in charge of the slip portion would remotely uncouple the coach. In GWR practice the brakes would be applied immediately as the vacuum was broken. The guard would then control progress by releasing the brakes using the reserve vacuum in the cylinders on the underframe and (hopefully) bring the coach to a smooth halt at the platform face. This did not always work and an engine had to be despatched to rescue the stranded vehicle. Where greater seating capacity was required, standard stock would be attached behind the slip coach itself. The provision of controls at both ends enabled the coach to be used in either direction without having to be turned. There were many slip coach services over the GWR with the coaches going on from their slip points to other destinations.