Railroad Signals Landing Page
Under construction! (not really)

Some helpful and informative links:

Jovet’s Signal Rules Sheets

Al Krug Railroad Signals Explanation (Archive) External link

Carsten S. Lundsten’s Guides on North American Signaling Practices External link

Eric Haas’s Photography Site External link featuring several signal collections

The Signal Page – World-wide Signaling Resources External link

How U.S. railroad crossing signals should flash, viewed from above:

Virtual Railfan Waycross, GA Southbound Jesup Subdivision Jct Signal: