Automatic train stop normally makes a penalty application for ANY restrictive signal -- in other words anything other than high green -- that is not acknowledged within a specified amount of time.

So, both the first flashing yellow and the solid yellow would have had to have been acknowledged.

This is what would happen with the most basic system. With a more sophisticated system, the system would have some indication of the maximum permissible speed and would also have either produced a warning for excessive speed and/or produced a penalty appication simply due to speed.


Yes, you would still have a penalty application at a red signal, too, but normally the train would not have gotten that far. The penalty application at the red would not do much for you if the red is at the end of a siding where the train is to stop for a meet and the train passes the signal at substantial speed.

But, if the red is for one train following another, and the previous train is far enough into the preceding block, the penalty application would still be useful and would most likely avoid a rear-end collision.

-- Ernest