Saturday, May 7, 2022

Union Pacific to Abandon ATC and ACS Effective June 1, 2022

 Well after about 18 months of regulatory approval, Union Pacific is set to remove all mention of the CNW Automatic Train Control and more general Automatic Cab Signals from the rulebook effective June 1, 2022.  As explained before the legacy CNW ATC system was super clunky and was definitely not worth keeping in the face of PTC.  The ACS seems to be more of a cost cutting move as coded track circuit cab signals can compliment ETMS PTC as demonstrated by Norfolk Southern.  However Union Pacific's cab signal implementation had some shortcomings that would have likely required additional modifications to make a joint ACS/ETMS system work well. Anyway, the real loser are the Employee Timetables which are set to lose a substantial amount of their color palette.


It was mentioned that Union Pacific will still require ACS equipped lead locomotives in some areas, which I am assuming is the Hiawatha Sub as that served as Union Pacific's "Rule 562" experiment and lacks wayside signals. The Hiawatha has Aspect Change Points every 1.5 miles, in line with the PRR/Conrail/Norfolk Southern practice. It is also important to remember that in most cases the ACS codes will remain in the rails as they are used to transmit block state.  Engines will either just run over the territory with their ACS fully inoperative or simply not present. Anyway, if you want a copy of the current UP Rulebook with the ACS and ATC sections intact, download it from the official site now. If you're reading this in the future, I saved a copy of the final revision with the ACS/ATC material.


2 comments:

  1. Hi Jersey Mike.
    I just saw a news article in Trains and it stated that the UP is keeping their cab signal system on their divisions west of Cheyenne.
    https://www.trains.com/trn/railroads/locomotives/in-service-cab-signals-on-mainline-railroad-routes-august-2022/
    This seemed odd to me as I was under the same impression as you that the abandonment of cab signals was system wide. I commented asking for details but no one responded yet.
    Do you have any idea what this is about? Thanks!

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    1. Thanks for the link and always nice to see a journalism major describe coded track circuits as "antiquated" since cab signals were baked into the PTC system in the Northeast and Norfolk Southern also integrated them into their ETMS cab signal system.

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