Bletchleyite
Veteran Member
Yes, the doors alone are enough for me to reject completely the assertion that Mk 3s even attempted to be the "best possible intercity train of its time".
Indeed. Sliding-door EMUs were already a thing before the first Mk3s were being developed, e.g. the old Merseyrail units or the Class 303s. Thus, the Mk3 doors should basically have looked, from new, like the retained ones do now. Using non-locking slamdoors was just nuts.