Document Revision History
Added "F"-sign to signals. Added Dwarf Signal to bridge with Protection
Signals. Updated "Spurs on the line, without line block system" to current
rules. Added to description to "Spurs on the line, with line block system".
Added Printer Friendly Page.
First non-draft version.
Significant errors in the explanations of Protection Signal for movable
bridge (without line block) and for Automatic Block and Protection Signals
History Document created.
Version prior to History Document.