actually, that was the setup they were planning for. remember the cross platform transfers with the straddled OL at east harbour?That's not the best way to allocate the capacity on that line - it would be far more efficient to allocate one set of tracks to local/stopping trains, and one set of tracks to express trains. This way, the trains on each set of tracks will have a similar set of stopping patterns and speeds and performance.
that required a fly-under at scarborough junction. which now that the OL tracks are together, theres no need for it really.
its going o be up to the oncorr contractor to build it or not