Thanks both - it was a new one on me, and I haven't been out that way recently so hadn't spotted the new crossover. I guess it's useful for flexibility, especially since Edgware Road can be a bit busy - meaning additional (beyond the normal schedule) reversals can't be fitted in there easily.
And since the "Circle" became the whatever-it-is-now, I've often wondered whether the extra services between Hammersmith and Paddington / Edgware Road that were enabled by that were always needed (or indeed could fit in easily) further east, so somewhere for trains from Hammersmith to run shorter return journeys makes some sense. (Though in terms of having similar service levels along the line, a reversal at Baker Street would be ideal - but of course that's logistically impossible with the existing trailing crossover being east of the station.)
Also, this Paddington reversal facility means that the Hammersmith branch and the actual circle could easily be run independently if required during disruption. (Is there still anywhere for the eastern section of the H&C to be turned west to east at Aldgate East, to enable that part to be operated separately too?)
