THE ORIGINAL number of coach types proposed by Serco Caledonian Sleeper was reduced to four when the proposal for sleeping pods was dropped following safety concerns, a development which reduced the tooling required to model the trains. A sleeping pod coach and a pod/sleeper composite were swapped for standard sleeper coaches in the order for 75 vehicles placed with CAF.
Introduced in 2019, the Mk.5 sleeper coaches are all of the same length, unlike the stock it replaced. Coach length was determined by the original length of the original Mk.2 and
