Is this the old rule under BR if the service is under a hour they have no legal obligation (like cathcart circle)?
The 313's came into service on the Moorgate to Hertford North and Welwyn Garden City (Initially Drayton Park to Moorgate shuttle only) route on weekdays and from Kings Cross at the weekends. I know I worked on them as a guard. Many a time have we stopped at a station, for someone to make an urgent dash to a toilet (Normally Driver or Guard, but also members of the public). Some 313's were moved to the South Coast, where the journey time is much longer than an hour. I am still amazed they are still in service since 1975, when they first were brought into training service out of Hornsey depot.
Originally from Hertford and know the route well. Never knew if the train back then was a 313 or 314, found your post very informative, thank you now if only I knew the train used on the Hertford east line back then too.