If one looks at the London rail and tube map, Zone 5 appears to be a bit of a waste of space. Compared with both zones 4 and 6, there are far fewer opportunities for single-zone travel as there are very few radial routes at this distance from the center of London. The only principal local transport is the Croydon trams, which already operate on their own fare structure.
I would propose reassigning stations to zones 4 or 6 on a case by case basis, and renumbering the zones accordingly. The new expanded "zone 5" would have a price point somewhere in between the current zone 5 and zone 6 fares, reducing the fares marginally for zone 6 travelers and increasing them for current zone 5 travelers such that there is no net loss of revenue to TfL/the DfT.
But why bother, given the up front cost to TfL, and National Rail operators? To my mind, reducing the cross-town fare for communities like Ruislip/Harrow, Orpington/Bromley, Bexley Borough, and Croydon/Sutton serves local residents making trips well outside of the centre without doing any damage to commuters. It would reduce loadings on a small number of local buses, simplify the tube and rail map, and (in the very specific case for non-contactless Oyster) create another zone for use elsewhere.
I would propose reassigning stations to zones 4 or 6 on a case by case basis, and renumbering the zones accordingly. The new expanded "zone 5" would have a price point somewhere in between the current zone 5 and zone 6 fares, reducing the fares marginally for zone 6 travelers and increasing them for current zone 5 travelers such that there is no net loss of revenue to TfL/the DfT.
But why bother, given the up front cost to TfL, and National Rail operators? To my mind, reducing the cross-town fare for communities like Ruislip/Harrow, Orpington/Bromley, Bexley Borough, and Croydon/Sutton serves local residents making trips well outside of the centre without doing any damage to commuters. It would reduce loadings on a small number of local buses, simplify the tube and rail map, and (in the very specific case for non-contactless Oyster) create another zone for use elsewhere.