Bletchleyite
Veteran Member
The correct name of the Routeing Guide is in fact the “electronic National Routeing Guide” - or eNRG. It was coded by Fujitsu in the mid 1990s following discussions with BR pricing managers. Somewhere I have got the original specification - I think from 1995. As has been observed, it was intended to ensure that carriers did not end up being forced to carry the passengers of ‘other’ TOCs. It predates online journey planning, but could (I assume) have been used locally in travel centres and booking offices equipped with Journey Planner (the Fujitsu software product that showed what itineraries were or were not valid for a given ticket).
The eNRG is a later implementation of it. The original NRG was a paper book.