Southern 1981 1981 As described by the signal chart found at http://www.railroadsignals.us/rulebooks/sr81/sr81.htm which are reported as the 1981 edition. 20092010JMRI GregMcCartney gpmccartney@gmail.com 1 2017-03-07 GPM Initial version Clear Rule 301 Proceed. Normal Normal Normal Approach Diverging Rule 302 Proceed, approaching next signal prepared to take diverging route. Normal Medium Normal Advance Approach Rule 303 Proceed, preparing to stop at second signal. Normal Normal Normal Diverging Route Clear (Medium) Rule 304 Proceed through diverging route, observing authorized speed through turnout(s) or crossover(s). Medium Normal Diverging Diverging Route Clear (Slow) Rule 304 Proceed through diverging route, observing authorized speed through turnout(s) or crossover(s). Slow Normal Diverging Approach Slow Rule 306 Proceed, approaching next signal at Slow Speed. Train exceeding Medium Speed must at once reduce to that speed. Normal Slow Normal Diverging Route Approach Slow (Medium) Rule 306.1 Proceed through diverging route, observing authorized speed through turnout(s) or crossover(s), then not exceeding Medium Speed, approach next signal at Slow Speed. Medium Slow Diverging Diverging Route Approach Slow (Slow) Rule 306.1 Proceed through diverging route, observing authorized speed through turnout(s) or crossover(s), then not exceeding Medium Speed, approach next signal at Slow Speed. Slow Slow Diverging Approach Rule 307 Proceed, preparing to stop at next signal. Train exceeding Medium Speed must at once reduce to that speed. Normal Stop Normal Diverging Route Approach (Medium) Rule 308 Proceed through diverging route, observing authorized speed through turnout(s) or crossover(s) preparing to stop at next signal. Train exceeding Medium Speed must at once reduce to that speed. Medium Stop Diverging Diverging Route Approach (Slow) Rule 308 Proceed through diverging route, observing authorized speed through turnout(s) or crossover(s) preparing to stop at next signal. Train exceeding Medium Speed must at once reduce to that speed. Slow Stop Diverging Restricted Proceed Rule 309 Proceed at Restricted Speed. Restricted Restricted Either Stop Rule 310 Stop. Stop Stop Either