Fathers Day is this weekend, so what could be more appropriate than a carload of ties! Of course these ties weigh about 200 pounds each, come soaked in creosote and are just slightly less fashionable than most of the ties Dad will get this year.
Railroad ties are a vital but easily overlooked part of the railroad’s infrastructure. The ties both support the rails (and the trains upon them) and keep the rails in proper gauge. In North America, the vast majority of ties are still made of wood (preferably oak.) Some heavy mainlines have been converted to concrete ties, which have been far more common in Europe for decades.
Properly treated, a tie can survive many years under the rails. Wood ties are infused with creosote – a thick, sticky and stinky black tar. Like everything else, there is a lot of science behind cutting and treating these ties to ensure they provide the longest service possible the railroads.
It starts with proper cutting to ensure that the heartwood is in the center. Once properly cut to size, the ties must be dried prior to treatment. Drying requires careful stacking and can take up to eight months to reach the proper moisture content.
Next the ties are loaded into large cylinders. Creosote is added and then the cylinder is heated and pressurized (or depressurized depending on the method used) to force the preservative into the wood. The processed ties are then ready for shipment to the railroads. The best ties will go to the mainlines. Those that don’t make the cut may still be sold to short lines or used on branch lines and sidings.
At one time, most large railroads owned their own treatment plants. Today most have been outsourced. Koppers is the largest company and they are kept plenty busy. Railroads consume more than 20 million new ties per year on average.
Many of these tie treatment plants use their own in-plant narrow gauge railroads to handle the movement of ties in and out of the pressure cylinders. With untreated and treated ties both arriving by rail, the entire operation would make an interesting operation for a model railroad.
Railroads use a variety of equipment to get the ties from the treatment plants to their storage yards and on to where they are needed. Typically, older equipment is used for this work. Gondolas retired from revenue service are a popular choice. Not only do these company movements not earn revenue, after a few years of carrying creosoted ties, the cars’ utility for other loads is greatly compromised. Some railroads have rebuilt other cars for tie use as well. Norfolk Southern and Burlington Northern have both converted bulkhead flatcars with new gondola sides for example.
How long does a tie last? There are many variables that can affect that number. Natural defects in the wood are a big factor. So is the environment where the tie is laid and the track maintenance around it. If the ballast is kept properly sloped and clean, ties will last much longer even in humid climates. The amount of abuse inflicted by the trains also of course plays a role. As you would expect, heavily trafficked mainlines require replacement more frequently than sidings and ties on a sharp curve will be worn out faster than those on straight track.
A typical tie will last anywhere from five to ten years on a mainline. If traffic is not as heavy and all other factors are good, a tie can last twenty to forty years. Regular inspections ensure that ties are replaced as, or preferably just before, they fail. Construction standards also call for enough ties beneath the rails that should a single tie fail, it will not cause a larger failure of the track bed or a derailment – up to 3,000 ties per mile on a heavy mainline. Therefore with consistent maintenance, if a railroad replaces 1/5 (or potentially less) of their mainline ties annually it should always stay ahead of the curve.
Stacks of fresh, or old, ties are a great way to represent a tie replacement project that is about to begin or which has just been finished. Of course with the Lionel Tie-jector you can take it a step further and have some fun as you actually drop the ties around your layout. Today a track hoe on top of a gondola is a more typical way of unloading the ties on the prototype.
After the ties are replaced, the old ties aren’t simply left to rot by the side of the tracks (at least they shouldn’t be.) Old ties are also gathered as soon as practical after a work project and carted off for proper disposal or resale. Old hoppers and gondolas are popular choices for hauling off the old ties. An old hopper filled with used ties would be an eye-catching model and a great way to add a car that would otherwise be “too old” for your era to your layout.
Ties are an important part of the railroads’ operation. With a little creativity, they can add a lot to your model railroad too.