Tracking Freight Cars

How do railroads keep track of their cars? I've seen Union Pacific cars on CSX trains in Wilmington De.

Each railroad produces a report (electronically, today) of car reporting marks (initials) and numbers delivered to a connecting railroad specifying the date, time, and place of interchange. At that moment the connecting railroad becomes responsible for paying any car-hire charges due to the owning railroad. Formerly called per diem, the charges were by the day, running from midnight to midnight; when it became technologically feasible, charges were changed to an hourly basis. (Up until then, there was a mad late-evening rush on every railroad to deliver cars to connections by midnight; if you couldn't make it by midnight, well, no hurry, nothing to be gained by delivering the cars before tomorrow midnight -- now, every hour counts, and interchange moves are made whenever the cars are ready to go.) Cars with reporting marks ending in X are owned by other than railroads, such as shippers, and are recorded in the same way, although standard per diem rules (they're still referred to as that, although technically it's called car-hire now) do not apply. Each car is now equipped with a transponder which responds to scanners which are placed by the railroads at critical points, such as entrances to yards, to establish exactly which cars are entering the yard, and in which order. There is also an AAR database called UMLER (Uniform Machine Language Equipment Register), formerly a directory on paper, published monthly in book form, giving full information about each car by number -- dimensions, special equipment, etc.

The old way of tracking the location of railroad cars was done by reading colored bar codes like the one on this Ex Penn Central car (Red Arrow pointing) The only trouble with the system was if the bar code was damaged or dirty the track side scanner would have a hard time reading it.

The newer way to pick up Car details and locations is now done by a simple plastic transponder with a chip placed in it. The transponder is a Gary plastic thing approx 10 inches long and about 4 inches wide. The Yellow arrow points to what appears to be one on this Conrail Boxcar.

More modern Reefer cars now have GPS Devices on them and any customer or railroad dispatcher can log in and can check each car and can keep track of fuel levels, and the temperature in the car.