Let me add a bit to Otto's quote above, since when I joined AAR in 1977, the board of directors had just voted to end the ACI labeling requirement.
The multi-colored bar code was developed by Sylvania for the railroad industry in the late 1960s. It lives on as the single-color bar codes (black and white or green and white) on most food and beverage products. But of course food package isn't used multiple times; you throw it away, so there isn't much problem with the labels getting dirty. Unfortunately, freight cars aren't disposible and they don't get washed very often.
The industry tried washing labels and also coating them with Teflon (or something like it) to repel dirt, but nothing really worked. In the meantime, railroads had started installing video cameras on tracks entering yards, and making a recording on a VCR of each train as it came in. A clerk couuld then review the tape, checking off each car number against a computer-generated consist list. This worked pretty well, and largely obviated the need for an automated system, which is why the industry didn't look too hard for an alternative to ACI.
In the late 1970s, Fairchild Space and Electronics developed a passive tag containing a computer chip that could be interrogated by a microwave transmitter. No energy storage mechanism was needed; the microwaves themselves provided enough energy to the chip to enable it to transmit a code back to the interrogator. Fairchild approached the railroads with this technology, unfortunately just after they had agreed to end use of ACI and Sylvania had filed an anti-trust complaint against them.
But eventually the message got through, and in the 1980s Burlington Northern began testing a microwave-readable tag on a fleet of ore cars. This led, in the fullness of time, to the adoption of a labeling requirement by AAR in 1993. These are the same types of transponders as are used on toll tags for cars, but they were invented for the railroad industry.
When AAR required the labels, private car fleet owners were quite upset about the cost of labeling (some of them remembered the ACI debacle). A group of car owners even took AAR to court. They lost; the judge rendered a wonderfully amusing opinion. He said, "Of course you're right; AAR can't make you label your cars, but then they don't have to agree to operate cars that don't meet their standards". Truly Solomon-like; private fleet owners don't have to label their cars, and the railroads don't have to agree to use the unlabeled cars.
Randy Resor, aka "NellieBly" passed away on November 1, 2013. We honor his memory and his devotion to railroading at railroad.net.
