Irregular intervals on East London Line at weekends

[cyclonecap]

Hi all, long time lurker, first time poster.

I was just wondering why there are such irregular intervals on Overground services on the East London Line whenever one of its southern branches is closed - image attached shows northbound departures from Rotherhithe during this weekend's closure from Clapham Junction to Surrey Quays:



While an 8/9 minute gap may not seem much, it is a long wait given the usual frequency on the line and often the case with planned engineering work, leaving the first train after this gap extremely busy. Surely as this work is scheduled in advance and these weekend branch closures occur often, can a solution not be found which at least maintains an equal(ish) gap between each train?

[redbond]

Instead of retiming everything, train planning department just remove the trains from the branch that is closed and leave the rest as is (most of the time). The train planning department is quite small and also has to deal with all the other lines. It's just easier for them to do that, never mind what passengers/staff would benefit from.

[35b]

Not just that, but once on the main national network, services have to fit in with the rest of the timetable. It’s debatable whether rebalancing the ELL core to give even intervals would be practical once those impacts were considered.