Hi Mr. Bane,
The FRA understood and got it correct regarding that M of W flat. When the Judge in the Superior Court in Atlanta on Oct. 30, 1911 made his ruling the although he did not have proper jurisdiction, he ordered that all cars carrying commerce moving on the connected lines of the nation were to be considered in interstate commerce and came under the meaning of the SAA act. Again, this was because the train crews that had to work on those cars could not see without reading the way bill where the car was moving.
In this case he clearly did not cover the nature of Maintenance of Way work cars that did not carry commerce and were clearly identifiable to trainmen as such. A rotary or a steam crane could clearly be seen to not be of a type of "car carrying interstate (or as this Judge added: intrastate) commerce". The law that created the Safety Appliance Act (1893) had its limits of jurisdiction over the railroad, and the lawmaker clearly understood that limit as they worded that Act of Congress. It can not be changed without changing the U.S. Constitution by Amendment, giving the Federal Government right to control all commerce and not just interstate and foreign commerce.
They never covered logging railroad that did not carry commerce, but only thier own logs that no one was paid to move (no way-bills). Even in the very northern tip of New Hampshire there was a logging railroad that crossed over into VT and also into and out of Canada for it route to move logs. Probably the only international private logging railroad. It was run by the Connecticut River Co. No ICC here.