Denny D’s Did You Know

Unannounced Yellow Flags

With renewed testing for yellow flags coming, I thought a review would be helpful. There are increased distractions in the cab that require all of us to be alert. PTC, Trip Optimizer, the conductor’s log, fatigue, and personal issues. It is imperative that we all stay focused and alert.


GCOR 5.4.2 outlines display of yellow flags for temporary speed restrictions. Part B outlines the procedure for when you see a yellow flag which you do not have a slow order for.


The first thing to do is start reducing to 10 MPH. You must be down to 10 MPH 2 miles from the yellow flag. Remember, Cab Red Zone until you reduce to 10 MPH.


Once you are 2 miles from the flag, one of two things are going to allow you to resume speed. Notice the word “or”.


If you pass a green flag, when the rear of your train is beyond it, you can resume speed. The green flag must be 2 miles beyond the yellow flag to count. 


If you do not pass a green flag, the other item that will allow you to resume speed has two parts, and you must do both. If the dispatcher informs you that there is no applicable restriction, you cannot resume speed until the rear of your train is 4 miles beyond the yellow flag. Notice the word “and” in this part. If you’ve already gone 4 miles beyond the yellow flag and still have not reached the dispatcher, you cannot resume speed until you do.


Yellow flag - Be down to 10 MPH two miles from the flag.


Resume Speed - (Rear of Train)


Green Flag (must be two miles beyond yellow flag to count).




4 miles from yellow flag AND dispatcher.








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