Railroad Classification Yard Chicago and North Western Railway's Proviso Yard in Chicago, Illinois, December 1942. PD-US.

Railroad Classification Yards

Classification yards have been around as long as railroads have, although unit trains of automobiles or other commodities are increasingly common. Some yards are huge—Union Pacific’s Bailey Yard in North Platte, Nebraska is one of the biggest at 2,850 acres, and measuring eight miles by two miles. Bailey has 17 incoming and 16 departing tracks, broken down into 200 tracks for classification and train building; not surprisingly, locomotives are also serviced at three separate shops at Bailey.

Union Pacific’s Bailey Yard Union Pacific’s Bailey Yard courtesy of Google Maps

How a Rail Yard Works

It’s probably not too far off-base to think of a classification yard as a huge filing system or warehouse—it’s a system for breaking up, sorting and reconfiguring trains, but it’s also one of the most complex operations of any railroad. Managers have adopted industrial performance improvement methods and applied them to yard management, breaking bottlenecks and improving the efficiency of yard processes. With improvements in handling and management, freight cars now linger in a yard for 24 hours or less before moving on to their destinations.

When a freight car enters a yard, it is shunted on to a lead track; from there, it is sent through a series of switches to its classification track. Larger yards have the lead track situated on a small hill, or “hump,” where the force of gravity can send the car through the proper switches; pneumatic or hydraulic retarders manage the car’s speed safely as it is routed and staged onto the proper classification track.

Yard work gets tricky when dealing with full cars, empty cars, heavy or light freight, or the occasional mismarked or unmarked rail car. It’s the yardmaster’s job to make sure that the staging of cars and building of outgoing trains goes properly; not surprisingly, modern yards use technological tools to get real-time information to the yardmaster.

Axle-counting sensors are spaced around the yard; the network of sensors can track the movement and disposition of every car in the yard and calculate the remaining capacity on each track. When tied in with information from the yard’s car-management database, this information can be used to compile reports of the actual consist of every train. Sensors can even be used to calculate the right hump speed for each car, cutting down on misroutes and enhancing safety.

The world of moving freight is changing, with more and more containerized and unit trains, but there will always be a need for the classification yard and its lengthy network of lead tracks, sidings and classification tracks.