I hope people won't mind me plugging it here, but my first book, a
history of the Bakerloo Line, was published by Crowood Press a few days
ago.

It is available in print or electronic form from the publisher at
https://www.crowood.com/details.asp?isbn=9781785007453
or (I hope) from all good booksellers. If you do buy it, there's some
extra material and a few errata available at
https://www.davros.org/books/Bakerloo.html

--
Clive D.W. Feather