Special Announcement Good news! After over a year, I have a source for the ATCS monitor once again! The image capture and automated FTP (sending the image here to the website) have been a bit sporadic though, so check the date-time stamp on the image to see if it is up-to-date. We'll give this a shot again!

Welcome to the active ATCS Display for the Moffat Tunnel Subdivision. ATCS is an acronym for "Advanced Train Control System", and it is a system that more and more railroads are starting to switch to. Rather than using trackside code line, ATCS uses radio waves to transmit control information (e.g. signals, switches, block indication, etc) to and from CTC control points. All the information going back and forth between the dispatcher and the control points can be picked up on a radio scanner and decoded. Using software (see www.atcsmon.com for more information), the decoded information can be represented on a CTC-style display. The display is online and it refreshes every minute.

Shown here is a real-time CTC display as of the date and time in the upper right corner of the image. White lines represent the track between the Pecos Street Crossover (CP DS004) and West Crescent. Due to the mountains between Crescent and East Portal, that section of track still uses code line (rather than ATCS) and cannot be monitored. Here is some information that should help you understand what you are seeing: * Any control point name (e.g. "West Crescent", "Arvada", etc) that shows as red or blue has been "refresehed" with data within the last two minutes of the screen capture. Control points shown in white have data that is more that two minutes old. *A green signal indicates that the dispatcher has setup the signal, presumably for train movement. Red blocks on the display show track indications. These could be the result of a train (most likely) or maintenance of way. *"T+T", which appears below the track indication, means that "track and time" has been given to maintenance personnel within the limits displayed on the screen. *Control point that appear in red are point that receive both signal indications as well as block indications. Unfortunately, five control points (East Rocky, West Leyden, Arvada, C & S Jct, and CP DS004) typically only have signal indications (no block indications) and are show in the display in blue. This is a result of two slightly different ATCS systems being used by Union Pacific. As a result, you (typically) cannot tell when there is a train at Arvada, for example, but the signals should give you a good idea of where the trains are (or will be soon). *Finally, if you notice a light blue box around a switch, that indicates that the switch is either being thrown (by the dispatcher), or is currently not in power. Sometimes maintenance of way crews will takes switches out of power so they work on the switch. Okay, that should be everything you need to observe trains moving over the 30 mile stretch from Pecos Crossover to West Crescent! Enjoy!

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