Coming in abit to this discussion, I'm afraid. My copy of the Permanent Way Institute's 'British Railway Track' is the 3rd edition, 1964. The first edition was in 1943 and the second was 1956.
Another useful book is 'A Handy Platelayer's Guide' published by Thomas Summerson & Sons of Darlington in 1895. It provides data for points but not slips in eight gauges from 18 inches to standard. Somerson's were makers of track components and were contractors for putting in sidings etc. Worth loking for, I think. I got my copy from seconhand bookshop in Birmingham that is alas long gone.
Bull head track can still be seen at Birmingham's New Street station! Judging by its appearance I don't think any of it has been used for a very long time and, if I remember rightly, the point connecting the Stourbridge Town branch to the main line is also still bull head.
Regards to all, David.