This is interesting. But let me add a few points.

1. Turning crossrail trains back @ Paddington is just crazy when there
is a lack of capacity in the mainline station.

2. Better for now just to electrify one mainline, i.e. Paddington to
Maidenhead.

3. We are stuck with the Central Line to West Ruislip because of the
depot.

So, better drop the Central Line into a tunnel for the Ealing Broadway
to West Ealing Stretch. Have the Central Line take over the Greenford
Loop.

Then extend the instead of turning back crossrail trains at Paddington,
reverse them from new platforms at Ealing. These platforms would
replace the Central Line tube platforms.

Then, use some of the freed-up terminal space at Paddington to for some
Chiltern trains from Birmingham.

Adrian.