Met to Addiscombe in the 1930's.

Things are never quite as simple as that. The link was the St Mary's curve between Whitechapel and Aldgate East. It was only removed with the East London line becoming part of the Overground.

New Cross and New Cross Gate both used to have connections to the main line and through trains used to run to/from Southern.

There was also a link from the East London line at Shoreditch which allowed access to Liverpool Street.

Thanks-I've found out there is a long article on Addiscombe in London Railway Record #14, so I've emailed them to see if they've got it in the Library.

It was in fact a 1925 scheme that was abandoned in 1930, so wasn't far out & apparently serious costings were made at the start, so, if I can get something definitive, I'll let everybody know.

The single line signalling only became necessary when A stock, which was more generously proportioned than some other stocks, was introduced to the ELL.

I think you are confusing "The Naval Treaty" with "The Bruce Partington Plans", as it is the latter which involves the Underground. The text specifically states that the body was deposited on the roof of a train near Gloucester Road (presumably at the convergence of the Circle and District, where trains were (and are) often held at signals) and fell off as the train negotiated the junction at Aldgate.

You are correct regarding 'The Bruce Partington Plans'. I need to read this (and 'The Naval Treaty') again. It hadn't occurred to me that the unfortunate corpse had travelled on the District, rather than the Met, despite the obvious fact that the former has far more instances of overlooking adjoining property.
St. Mary's curve has been abandoned, then? Another blow to flexibility.

Firstly, as I described on another thread, the Metropolitan Railway company thought itself a cut above the other 'tube railways' serving London - offering a Pullman car service in to the City from Aylesbury for example. It was only after the formation of the "London Passenger Transport Board" in 1933 (an event the Metropolitan Railways management and shareholders bitterly resisted) that the Metropolitan line became more integrated with the other Underground railways that make up todays 'tube' / Underground system

Secondly The loading gauge of Metropolitan line trains are virtually identical to mainline ones - as such there would have been no need for separate 'tube' (as in deep level lines) platforms to serve such stock. If additional platforms were needed they could have been built at standard UK height and used by both Met and SR trains.

Thirdly, out of all the 'big four' companies created in the 1922 grouping the SR was unique in that it earned far more from passenger traffic than freight. The LMS / LNER / GWR focused their attention on express services and serving UK industry / mines and were not particularly bothered about suburban traffic - regarding it as a bit of a nuisance. Hence when opportunities came along to hand over suburban routes to the LPTB, the GWR, LMS & LNER were quite eager to cooperate. By contrast, the Southern Railway regarded the large revenues generated by commuters as something to be protected and essential to the company's financial well-being. Don't forget the District had wanted to extend from Wimbledon to Sutton but were frustrated at every turn by the LSWR, then the SR who were determined this should not happen - with the result we see today. As such the SR (as with its predecessors, the LSWR, LBSCR and SECR) was incredibly hostile to encroachment by the 'tubes' / Met / District. This was helped by the large investment previously undertaken by electrification by the aforementioned companies, which with the commitment by the SR to continue the process, meant that the SR could quite legitimately say that suburban traffic south of the river should be left to them and the 'tubes' / Met / District should concentrate their efforts north of London where suburban improvements were well down the list of the GWR / LMS / LNERs prorities.

Fourthly, even back in the 1930s, the four tracks from New Cross to Lewisham were very congested and just as there is no way of fitting the Overground through that section without removing SE services to London Bridge, the same would have been true of SR services. Expansion to 6 tracks would have been expensive for the Met and with the SR being hostile, securing the necessary powers was unlikely to happen.

In reality I suspect it simply boils down to the fact that the Metropolitan Railway Company (not the Metropolitan line management of the LPTB which only came into being post 1933) was rather frustrated with the low use / profits being generate by their stake in the East London line* and wished to improve them. Its not dissimilar in principle (making better use of an underused asset) to the various proposals they put forward for a time which linked the Northern City Line** to the Metropolitan line proper. With the SR hostile it stood very little chance of success but the Metropolitan possibly thought it worth a go.


*(yes, this was purchased from the original owners by the Met in 1913 and didn't become a part of the Northern line until the mid 1930s when the LPTB had forcibly taken over all the previous railway companies concerned)

**a joint enterprise owned by the Metropolitan Railway, District Railway, SR (successors to the SECR & LBSCR) & LNER (successor to the GER)