20092010JMRI DickBronson PaulBender 1 2010-01-01 DB Initial version 2 2010-01-12 PAB Adapted from NYCS-1937 3 2013-07-09 PAB Add aspect mappings and signal icon references SLSF Single searchlight grade signal As described in the July 1978 Revision of the St. Louis San Francisco Railway Company publication "RULES for the Maintenance of way and Structures" effective July 1,1973, chapter titled Description of Signals. As noted in the source material, these rules are rules of the Frisco Transportation department. Appearances for a single-searchlight signal head with a G (grade) marker and number plate Clear green Rule 281 ../../../resources/icons/smallschematics/aspects/SLSF-1973/SL-1-high/rule-281.gif Approach yellow Rule 285 ../../../resources/icons/smallschematics/aspects/SLSF-1973/SL-1-high/rule-285.gif Approach Medium flashyellow Rule 284 ../../../resources/icons/smallschematics/aspects/SLSF-1973/SL-1-high/rule-284.gif Restricting lunar Rule 288 ../../../resources/icons/smallschematics/aspects/SLSF-1973/SL-1-high/rule-288.gif Grade red Rule 289 ../../../resources/icons/smallschematics/aspects/SLSF-1973/SL-1-high/rule-289.gif Grade Grade Stop Approach Stop and Proceed Approach Grade Approach Restricting Approach Diverging Approach Approach Medium Diverging Clear Approach Medium Approach Approach Medium Approach Medium Clear Approach Limited Clear Advance Approach Clear Clear Clear