I am currently reading an old Railway Magazine - Nov/Dec 1948 and to be precise, p. 420.
The following information has been given in answer to a reader's question regarding the Metropolitan District Railway, "An embankment was formed for a projected connection between the District Railway and Great Central Railway, at South Harrow, but the works were never completed."
These works can be seen here on the NLS site. Can anyone shead more light on this aborted connection and the reasons behind the project.
I appreciate that this LUL line is now the Piccadilly Line and the Mods may think it better suited there.
Interesting. I often wondered about that little area, now wooded, when I used to commute that route on the Picc. The 1945 view on Google earth is less wooded and maybe shows a path. Sorry I know nothing else about it. It would have been a very steeply graded link though. Perhaps it was thought useful to bring new rolling stock or wagons of material in and out of the District Railway.
I know there's a bit about it in the late Mike Horne's two-volume book "London's District Railway". Can't remember which volume though.
The District were always desperate to try and attract companies to use their lines to reach central London. At one point there was talk of the proposed "London & South Wales Railway" (a new mainline to rival the Great Western) using District tracks from west London to a new terminus in the Earl's Court area. The South Harrow spur may have been a hangover of that scheme, perhaps?
Also worth noting the recurring proposals for the Met or District to reach High Wycombe by their own railway extensions.
Had a closer look via a bike ride and studying Google Earth. It appears the linking gradient needn't have been as steep as I'd suspected. About 400m west of the Picc line tracks there is a bridge carrying Wood End Avenue over the GC lines. This bridge is clearly built to span four tracks, with the current ones through the northern half of the bridge. So any link would only have to reach the same grade at about this location. Also it looks like the railway land take allowed space for this sort of thing as the only buildings are a set of much more modern apartment blocks close to Northolt Park station. The Wood End Avenue bridge is now only open to pedestrians and cycles, but is built for a slightly wider roadway than the adjacent street width. Maybe it was designed to be significant as a station entrance to an expanded Northolt Park station.
Weren't sometimes projected embankments formed out of aspiration, yes, but also as spoil dumps to take the material excavated from further down the line? The two never-used embankments which would have forme linking spurs to and from the T&H withe the Enfield Town line might be so? But I don't know the GC/MDR area.