In message , Tom
Anderson writes

There is another option - if trains didn't visit Clapham Junction at
all, they could go from Imperial Wharf to Wandsworth Road directly,
without reversing. I don't have a track map to hand, but ISTR that this
can be done without conflicting movements across other tracks.

That is certainly true, but loss of connection at Clapham Junction
(Britain's busiest railway station) would be a serious loss and would
need the retention of the now popular Clapham-Willesden service, thus
restricting the viability of an 'orbirail' service that by-passed
Clapham Junction.
--
Paul Terry