TheOneKEA wrote:

Northolt Junction to West Ruislip would be very easy to restore as
well, and in fact really should have been done a while ago - the
Ruislip branch of the Central Line may benefit from an increased
Chiltern stopping pattern at West Ruislip.

Although the down platform at West Ruislip occupies the trackbed of the old
down slow line and would need to be demolished and set back again to its
original alignment. Likewise the up platform at Gerrards Cross (and, as you
mention, the new down platform under construction at Denham).