In the mid to late 1960s, British Rail (BR) was searching around for ways to increase efficiency, and came across the TOPS system in a 1968 presentation by an IBM US Transportation Industry Representative, who shortly after, formed IBM World Trade Corp's Transportation Industry Centre in Brussels (E.
Sequentiality was all that was required, but with the requirement to renumber, it was decided to adopt a logical system for classification, and the five- or six-digit TOPS number was divided into two parts.