With so many types built, the changing railway during the second half of the 20^th century meant that certain types of Mark 1 were made obsolete before others and despite some examples running for over 40 years, others were withdrawn and made available for preservation much earlier. As vacuum braking and compartments became less favoured, Mark 1’s fitted with such equipment were condemned and made available to heritage railways.

The NNR was a pioneer in preserving Mark 1’s and was the very first heritage line to obtain one (E3868) as long ago as 1969. Many hundreds followed around the UK and the Mark 1 became as successful in preservation as it was for British Railways. Key to this success was their availability at the same time as the preservation movement was aggressively growing, along with a powerful combination of them being historically suitable to pair with steam engines but also being “modern” enough to be built fully of steel. This in turn meant they could withstand being run with less maintenance whilst being stored outside in the elements, both of which were common in those embryonic days. Even today, the bulk of the Mark 1’s resident at the NNR still require berthing outside all year round, so their durability is essential to their continued survival.