Last week we looked at how a local crew picks up and sets out cars. Rarely will a car that is picked up at one siding like this be delivered to its destination by the same crew or train. Instead, these cars are taken to a yard where they will be switched into new trains headed all across the continent. Like the work of the local crew, switching in a yard is labor intensive. But pace of work here is much faster and the operations far more intense.
The action begins when our freight train arrives in the yard. Most yards have a designated track, or tracks, for arriving trains. Here the locomotives and caboose are removed and go to appropriate tracks for service.
In some cases, trains are blocked for different destinations. If this is the case, then the entire train does not have to be switched. A yard engine (or sometimes even the road engines if they will remain with this train) will take the appropriate blocks off and move them to other classification tracks and add any new blocks to the train. This switching is often done with the air brakes still charged, much like the operation for setting off / picking up a single car described last week.
Other reasons for blocking a train would include special cars like stock cars or reefers which may have to be switched to a separate area in or near the yard. Here livestock can be given their rest and reefers can be iced.
If the entire train needs to be reclassified here at the yard, the process will be a lot more involved. Since nearly every car will be placed on a different track, this switching is usually done without any air brakes on the cars. Before starting, the air will be bled out of the reservoirs on each car. This will make the work go much faster, but does add to the danger level as well.
Since cars without air will roll very easily, most yards are designed as a bowl – the tracks slope slightly downward away from the switches at each end. This way if the cars do roll, they won’t come back to the switches where they could derail or strike another car.
The incoming cars will be switched according to their destination as shown on their waybills and car cards as we’ve discussed earlier. Each classification track in the yard holds cars for a different destination. Some of these tracks may be for local customers, others will be for other yards. It is not uncommon for cars to pass through several yards along their journey.
Cars can now be switched in one of two ways. “Hump yards” are designed with the throat, or switches, of the classification tracks on a large hill. The switcher simply pushes slowly and steadily forward from the back of the train. The first car is uncoupled at the top of the hill. Switches are lined for the appropriate track based on the car’s destination. Gravity carries the car to the proper track and the process repeats for the next in line.
Most modern humps use remotely controlled switches and pneumatic “retarders” to slow the car to the proper speed so it will roll to a gentle stop or couple with other cars in the track. Scales weigh each car at the hump and computers calculate the proper resistance at the retarder so the speed is just right based on weight, the number of cars in the track, even weather conditions. Prior to retarders, brakemen would ride each car down the hump and use the hand brake to control its speed.
Where a hump isn’t available, the cars are “flat switched.” Again, even a “flat” yard will have some grade for safety.
Instead of simply pushing ahead, when flat switching the locomotive must push the first car to its designated track then reverse through the switches. Tracks are lined for the next car and the switcher pushes ahead again. Back and forth, track to track, the process is repeated until each car is sorted. Flat switching is much more labor intensive. It can also be more time-consuming.
With a well-designed yard, a good switch crew can often keep the cars moving almost as fast as a hump however. Crews will often use the slight grade of the yard to their advantage as they “kick” cars into the appropriate tracks. Once the switches are lined, the train pushes ahead. As the car nears the switch, the brakeman pulls the coupler pin before the train has stopped. Now the engine slows and the car keeps rolling. As the car rolls into the track, the engine has already reversed and is making its way to the next switch.
Assembling Outbound Trains
In addition to breaking down incoming trains, the yard must also put together trains for departure. Most yards are designed so that these operations can take place at the same time.
Once a classification track has been filled, or when the train for that destination is scheduled to depart, its cars are pulled and placed in a departure track. An outbound train may have several blocks of cars from different classification tracks. This process is much like the arrival yard in reverse. Once assembled, the cars’ air hoses are connected. Some yards have a stationary air supply that can be used to build air pressure before the locomotives arrive.
When departure time comes, locomotives and a caboose are added to the train. An air test is performed to make sure all of the brakes are working properly. The conductor confirms that the cars in the train match his paperwork and they are ready to roll.
On Your Railroad
All of this action can be a lot of fun on a layout. Even very basic waybill cards for your cars can turn a few switches and sidings into a great switching game. Designate specific tracks for specific destinations. When the train arrives, grab your switcher and your paperwork and get moving. For more on building a working classification yard, refer to this previous blog article.
Once you’ve filled a track, make up a new train and send it on its way. No two trains will ever be the same and even if they just make a few laps around your railroad before coming back to the yard to be reclassified, you’ll never run out of work to do in the yard. By incorporating a separate yard switching lead track from your mainline, you can switch cars in the yard while your other trains continue to run.
By the way, kids love helping you switch a train. It’s a great way to share the hobby and exercise the brain. This simple level of interaction will hold their attention much longer than simply watching the train run in circles. Plus, when all the cars are switched there is a new train run.
Next week will add one more level of interest to your model railroad operations – cars that require special handling.