http://www.trainorders.com/discussion/read.php?2,2128450<br /><br />CSX in the past few years has had THREE sets of signal aspects &amp; indications:<br /><br />-- &quot;Seaboard&quot; signals, found on former SCL, L&amp;N, et al territory. These are designated by their rule numbers without prefix of suffix letters.<br /><br />-- &quot;Chessie&quot; signals, found primarily on former B&amp;O/C&amp;O/WM lines. this includes all aspects found on the CPL signals. These signals carry the same rule numbers, but prefixed with a &quot;C&quot;, e.g., C-281 (Clear)<br /><br />-- &quot;Conrail&quot; signals, found where you might guess. These are the NORAC Signal Aspects and Indications, rule numbers prefixed with a &quot;CR&quot;, e.g., CR-281.<br /><br />All three sets of aspects and indications are speed-based, that is the home signal at a control point would display either Slow, Medium or Limited Clear depending on turnout speed in the route vs. the &quot;one-size-fits-all&quot; Diverging Clear typical of western roads.<br /><br />Probably the biggest difference between the various aspects is the Seaboard rules allow lunar aspects for Restricting, whereas Chessie/Conrail aspects use the tradional (for them) bottom yellow. I haven&#039;t seen the latest CSX book, so I don&#039;t know if CSX has embraced the flashing red aspect for Restricting like the GCOR roads. If they&#039;re using LED signal heads I&#039;d guess they have.<br /><br />The special instructions for each subdivision will tell you which set of signal rules are in effect.<br /><br />CSX System Standard for new installations is the Seaboard style. When they re-installed the second main from Pine Jct. IN to Willard, OH the CPLs were all removed and color lights conforming to the SBD aspects were installed.<br /><br />In my ticket-punching days at Amtrak, I had to know the Chessie signals to work to Grand Rapids (they also had a couple of aspects unique to the ex-PM up there, like a green-over-green dwarf -- not a CPL-- for Clear) and the SBD aspects to work to Garrett, IN or the ex-Monon to Indy. These little variances always made CSX rules classes, shall we say, interesting...<br /><br />NZ