Covered Carriage Truck was a type of van with end doors used for moving motor cars or parcel traffic. Four wheeled CCT were banned from British Rail

British Rail

British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...

 in the mid 1960s. These vans were designed to be used for carrying motor cars in Motorail but the tight clearances inside the body of the van and closing/opening of the end doors took a lot of time and effort from staff. The vans were replaced by General Utility Vans (GUV)

General Utility Van

A General Utility Van is a type of rail vehicle built by British Rail and its predecessors, which was primarily used for transporting mail and parcels. They were used by both Express Parcels Systems, the British Post Office and Railtrack. National Rail and some Train Operating Companies still use...

and car flats.