I've walked under the bridge in Ransome Walk many times over the years but only recently heard that it was built for a narrow gauge railway that ran from the ballast pit that is now the site of The Valley, down to a wharf on the River Thames.
The route of it can be traced on this old map
https://maps.nls.uk/view/102343435
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I'll guess that the church in the background is St Luke's with the chalk cliffs of what is now The Heights and The Valley in front.
There is an apparent bend in the railway line which isn't replicated on the 1870 OS map.
Today the only remaining branchline is that to Angerstein Wharf, for aggregat transfer and stockpiling, which leaves the North Kent Line west of Charlton.
Look them up on the NLS georeferenced maps website.
Seems the Victorians didn't care about anything East of Greenwich. 😃