The 57′ bow-ended design followed on from the 70′ coaches introduced in 1922 and were externally similar. When first introduced they went into premier express services, often in 6 coach sets, on trains such as The Bristolian and the Cheltenham Flyer. They were dispersed more widely as newer designs were introduced.
Right hand coaches had the firsts on the right when viewed from the corridor side, as depicted by this kit. Comet Models W8K is the left hand version, and the photos are actually of this.