A bit of an update in my researches into this rather odd nuget of railway history.
I am building up quite a good picture now of what happened and am picking up snippets of information from a wide range of sources to pad out the story.
There seems to be some references to parts of the river structure remaining for at least a decade after the railway firm collapsed, and even a possibility that the Whitehall tunnel was considered for reuse by the Baker Street and Waterloo (Bakerloo) railway when it was being planned.
I am now digging deeper into archives held by various government authorities to try and find more detailed records, as there is limited information at the Public Records Office – to flesh out the story.
I also now think I know who the construction firm was that had been contracted to build the cast iron tubes which would have lined the river bed – and wrote to the Museum of Docklands to see if they have copies of the contractors records this morning.
The difficulty with this project is that there seems to be limited direct information about the railway, so much of my reading now is based on reading up on other projects which may have overlaped or somehow run into the strutures constructed – for example, I found a reply to a letter from a surveyor on the Bakerloo line noting a long depression in the River Thames at the point where it was dredged for the pneumatic railway – now to find the original letter!
Overall, it is quite an exciting project and each time I find something new it just motivates me further to keep researching.
I would guess that I might settle down to do the main write up maybe in Decemeber over the Xmas break and seek a publisher for it in the New Year.