I’ve been doing quite a bit of research in an attempt to fully understand the fares for the Gatwick extension of the Oyster system. The results are nearly ready for publication, but in the meantime I have come to the conclusion that the current Oyster system is full. What do I mean by this?
For general fares the Oyster system has 16 zones. All stations served must fall into one of these zones unless the only fares available are special fares. Special stations include the riverbus piers, cablecar terminals, Stratford International NR station and platforms 13-14 at Victoria NR station. Everything else falls into one of these 16 zones:
1-9: Obviously the nine numbered zones on the London rail map.
10: Watford Junction and the Grays area stations.
11: Broxbourne to Hertford East stations.
14: Redhill and Earlswood.
15: Salfords and Horley.
16: Gatwick Airport.
So, any further expansion of the Oyster system will require the new stations to share any of the above zones and probably their fares too, or it will have to wait for completion of the back-office processing project. TfL are being somewhat reserved about the progress of that project, but it’s going to have to be finished before Crossrail/Elizabeth Line trains run to Reading. If it isn’t you’ll have TfL services where Oyster isn’t accepted.
No pressure there then!