This video from oorail.com is the fifth in a series explaining basic British Rail Terminology. In this fifth installment we follow on from the Mk1 and Mk2 videos to look at Mk3 (HST) coaches. This video explains the difference between Mk3 (HST) and Mk3A/MK3B (locomotive hauled) versions of the coaches. The video explains the different types of Mk3 coaches, how they are configured in a rake for HSTs and the difference between Class 253 and 254 HSTs. The configuration in this video is based on…