Effect of ICC 79mph limit

What was the effect of the 79mph limit on engines without cab signalling? I know the railroads preferred to stick to the limit rather than implement cab signalling. Was there a lot of running exceeding 79mpg prior to this? Were any schedules greatly affected?

The 79 MPH restriction is actually for trains without some sort of automatic train stop. Most railroads in the US used General Railway Signal's IIATS. The ICC law requiring it on trains traveling over 79 MPH only went into effect in 1951, so there was a surprisingly small amount installed. The Santa Fe, for example, was the only one to equip their Chicago-California lines. ATS was never popular because of the maintenance the system required. Most trains were officially scheduled to travel under 80 MPH, but of course sometimes the rules were bent. Rail passenger service was being pinched by this time.

NorthWest wrote:The 79 MPH restriction is actually for trains without some sort of automatic train stop. Most railroads in the US used General Railway Signal's IIATS. The ICC law requiring it on trains traveling over 79 MPH only went into effect in 1951, so there was a surprisingly small amount installed. The Santa Fe, for example, was the only one to equip their Chicago-California lines. ATS was never popular because of the maintenance the system required. Most trains were officially scheduled to travel under 80 MPH, but of course sometimes the rules were bent. Rail passenger service was being pinched by this time.

Installing ATS to allow passenger trains to operate at speeds over 79 mph was not popular in the 1950's, but the ICC had already ordered the 49 largest Class I railroads to install ATS in 1922. First on one subdivision and then a couple years later on a second subdivision.