Just out of interest, this is the response being given by Arriva at the moment (I had emailed in regards to the service frequency on Enfield/Cheshunt):
Not sure about the idea of splitting at Edmonton Green - would probably be quite operationally inconvenient, surely? Where would the trains cross over and reverse, which trains would continue through to London etc?
Quite rightly, its a terrible idea. Forget inconvenience, who is paying to re-signal and make those sections permissive? Splitting and Joining trains en-route in an inner suburban setup so small is absolute madness. For a train to go 2 stops on a branch (which is close to 1mile away) and 4 stops on the other every 15mins?
Lets not also forget the GA trains that regularly use the Southbury lines during the peak, disruption, football, and alot of weekends during engineering works.
As Arriva have quite rightly pointed out, until WA is re-written in its entirety, this subject is pretty pointless. WA runs at the moment with maximum utillisation with headways in multiple places as little as 1 minute between conflicting services (with appladuble precision when its on time to be fair) for Cambridge, Hertford, Bishops Stortford, Airport, Chingford, Cheshunt, Enfield. People keep forgetting its not just about LO. They simply look after 3 services within the West Anglia timetable. Easiest way to think of it. Which is why (give or take the odd minute) The timetable has remained virtually unchanged for a the past 10 years. Even the recent reshuffle of platform usage at Liverpool Street was considered as "outside of the box".