Caught on Camera: CSX's Gonzo Distant Signals

Distant signals, as defined as those that appear in otherwise unsignaled territory to warn train movements of an upcoming absolute signal (ie an interlocking), are seen in two flavors in the North American scene, fixed and dynamic. Many year's ago I discussed the use of dynamic distant signals on some Conrail Shared Assets lines in Southern New Jersey and although fixed distant signals are far more common, dynamic distants aren't remarkably rare. Today, most signaling systems make use of two possible distant signal rules. Approach the next signal prepared to stop and approach the next signal expecting a proceed indication of a type defined by route knowledge. As these appear in unsignaled territory neither of these conveys track occupancy information between itself and the absolute signal. CSX on the other hand defined its distant signals by a marker plate that, like the vomiting emoji, can be applied to any signal.

In practice the CSX App Marker would only be applied to Clear, Approach, Approach Limited, Approach Medium, Approach Slow and Restricted Proceed/Restricting. Basically anything that would normally appear on an automatic signal before an interlocking. Now of course this wouldn't be a "Caught on Camera" post if I didn't find an exceptional example of this system. In Cartersville, GA the unsignaled Cartersville Sub approaches the W&A sub at a wye interlocking designed BOWEN. At some point after 2012 CSX re-signaled the W&A sub and installed a new App marked distant signal right off Sugar Valley Road, seen below.

Unlike the typical dynamic distant with two lamps, yellow and green, this example has 5 lamps including a fixed yellow in the uppermost head. This was because the west apex of the wye was interlocked and could give a slow speed route and a medium speed route. Therefore the Sugar Valley Road distant can display Y/R/R Approach for a stop or restricting, Y/G/R Approach Medium for the medium speed route and Y/R/G Approach Slow for the slow speed route. Of course because it doesn't reflect track occupancy the most restrictive indication is Y/R/R Approach as seen here next to an approaching train movement. Ironically, the approach lit distant signal is indirectly reflecting the occupied nature of the block by being lit so at some level, the App Marker lies 😅.