I'm looking for a short story that I read 15-20 years ago.
The protagonist has escaped the apocalyptic pandemic by being within the Arctic Circle at the time. He somehow makes it back to the Northern British Isles and travels to London by rail. I believe he used a locomotive, but it seems more likely to have been a handcar.
In London,
he finds no survivors, and such a scene at St. Paul's that he has to flee from the smell.
He continues searching elsewhere
but still finds no survivors, and ends up philosophising by a stream or brook.
Edit: The story was in an anthology, possibly together with Bobo's StarBobo's Star and/or Ray Bradbury's There Will Come Soft RainsThere Will Come Soft Rains.