If you are unsure whether a particular routeing point for the origin station is the correct one compare the historic National Fares Manual data from September 1996 (NFM64) fare from that routeing point to the destination with the fare for the throughout journey - it is an appropriate routeing point only if that fare is the same or lower than the fare for the throughout journey from the origin station to the destination station.
Follow the same procedure if you are not certain that a particular routeing point for the destination station is the correct one. Compare the fare from that routeing point to the origin station with the fare for the throughout journey - it is an appropriate routeing point only if that NFM64 fare is the same or lower than the fare for the throughout journey from the origin station to the destination station.
All fares comparisons must be made using one of the following NFM64 single ticket types:
• Standard Open Single (SOS)
• Standard Day Single (SDS)
• Saver Single (SVS)
• Cheap Day Single (CDS)
In exceptional circumstances, due to local fares policies, a direct comparison may not be possible. If this is the case and the origin station or destination station has a lower fare of the type selected than all its routeing points, the Standard Single (Day or Open) fares should be used for comparison purposes. […]
Alternatively the Routeing Point Calculator can be consulted. This can be found in the Routeing Guide at Help and Instructions, between Section B (Pink Pages) and Section C (Yellow Pages). This tool will calculate eligible routeing points for a specific origin and destination. It also applies fare route data and appropriate easements from Section E (Easements). The tool will show the first station of a Routeing Point Group that a journey must go via, before passing subsequent stations within that Routeing Point Group.