This is from uk.railway courtesy Brian Robertson - Quote . . .
Long ago, on the 1st of August, 1936 to be precise, a certain James Milne, General Manager of the GWR, put his name to a new book of rules and regulations for company servents called the General Appendix. I have a copy and it is packed with fascinating drawings and photographs of.... signals and wagons and the mechanism for slip coaches and even the workings of a 'Tilly' lamp. Take a look. That and lots more.
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