Watford Junction and Shenfield special fare zones

[shinkansen1966]

Transport for London use 9 concentric zones to determine their fares. Zones 1-6, mostly correspond with the Greater London Authority area. There are exceptions and the eastern branch of the Central line springs to mind.

So why exactly do TfL go to the trouble of putting Watford Junction and Shenfield in special fare zones? Both station are served by TfL services. Both stations could be added to zones 7, 8 or 9.

Thanks for any help. Curiosity is getting the better of me.

 

[matt_world2004]

Transport for London use 9 concentric zones to determine their fares. Zones 1-6, mostly correspond with the Greater London Authority area. There are exceptions and the eastern branch of the Central line springs to mind.

So why exactly do TfL go to the trouble of putting Watford Junction and Shenfield in special fare zones? Both station are served by TfL services. Both stations could be added to zones 7, 8 or 9.

Thanks for any help. Curiosity is getting the better of me.

Fares are set by a national rail toc instead of tfl for these stations watford junction is set by London Midland and shenfield by abellio greater anglia

 

[Bletchleyite]

Fares are set by a national rail toc instead of tfl for these stations watford junction is set by London Midland and shenfield by abellio greater anglia

Indeed, it's basically so you don't have different fares for TfL and NR, instead tickets are interavailable.