I have a UPC scanner that I’d like to use on my future layout to automatically sort cars in my yard. The software I believe allows for variation in how the codes are encoded but I’d like to try and keep it like prototype, assuming it is used currently by rail systems. I understand the ACI system has come and gone but can’t find too much info on anything that might have replaced it.
The last time I saw a real train, I’m sure the cars all had what looked like a “standard” UPC code. My software prints the codes as well as interprets them and a little bit of computer control and automated turnouts, I should be able to do this automatically
Can’t say as I have ever seen a freight car with anything like a UPC code. The ACI system failed because the cars kept getting dirty, or the labels scraped. Having to also manually check the trains for the illegible cars rather defeated the original labor-saving intent. UPC codes would present the same issues.
New technology has appeared in the subsequent 35 years, and the cars are fitted with little transponder tags about frame level. Readers beside the track read them electronically (don’t ask me how) and this seems to be very successful.
I recall someone had a layout in Model Railroader where they were reading bar codes off the bottom of cars. Pretty easy with a USB reader. All you need is a software program to handle the data.
From the previous discussions (this comes up at least once a year on various forums), the issue seems to be finding a reader with a very narrow range that is cheap. For example if you want to know which track a car is on, the reader has to have a range of less than 1" (for an HO layout). If it has a larger reading radius, it will not be able to tell which track the cars are on and will read cars on other adjacent tracks.
If the reader radius is measured in feet It might read every car in a yard or the entire layout.