What's holding the track together?

Among all the things that are going on in railroading, some of them political, some safety-related, some very, very business oriented, we tend to forget some of the nuts and bolts of railroading. I don’t mean this in any figurative sense, either. Figuratively, there is today at least one eastern railroad where one might ask the question, “What’s holding the railroad together?” I think you know which one I mean. But that’s a political and business question.

Literally, I am talking about nuts and bolts—and spikes or fasteners and ties and ballast and whatever comes under that.

Time was—and those of you who are over 40 know this—when just about every kid who lived near a railroad cherished the thought of owning a genuine railroad spike. Spikes, as we all knew, were driven into the wooden ties to hold the rails to the ties. Rail sections were held together by joint bars, heavy steel bars placed on both sides of a joint and bolted through, often three bolts to a rail end, with large bolts secured by nuts that weigh almost a pound each. Ties were laid on the ground, which presumably was graded or otherwise prepared—perhaps compacted—to hold up the train. Ballast was placed around the ties to keep them from moving laterally. In mid-20th century, ballast often was never as deep as the height of a tie.

It was and is a pretty simple system, one that served the railroad industry well for over a hundred years.

As most of you know, the rest of the system involves flanged steel wheels on the top of the rails. The seemingly insignificant flanges do the job of keeping the train—all of it—on the tracks. Another simple concept, but one I will discuss on another day.

Times have changed, and with them the basic structure of track. Let me work my way up to what now replaces the old railroad spike.

Granted, 19th and early-20th century railroads used the equipment available to them to create grades and roadbed, the structure made of earth and ballast that carries the weight of the track. They did not have access to the spectacular heavy equipment that can be moved on highways and overland to almost anywhere that a railroad must be built or rebuilt.

Working back up to what now replaces the railroad spike, let’s start with the grade and subgrade. Modern new installations often start with something not unlike a highway. The soils are prepared—compacted and/or filled and replaced—and then crushed rock is followed by, well, a highway. Often this is an asphaltic surface applied exactly as one would blacktop a roadway.

Then comes the ties. While old ties were either untreated (very old) wood or wood treated with some kind of preservative like creosote, new ties are often concrete, plastic, or even steel. It would be kind of hard to imagine driving an old-fashioned railroad spike into steel, wouldn’t it?

It’s not necessary to drive spikes in today’s world of railroading. Concrete, steel and composite plastic ties are all manufactured with some kind of fastener or ready to apply a fastener that is different from the standard spiked rail on a tie plate. And wooden ties can be easily adapted for the new kinds of fasteners.

Did I mention tie plates? They weren’t even used in the early days of railroading. When engines and gross weights for freight cars were light, rail in the familiar American configuration could be spiked directly to the tie. Later, to spread the weight of heavier rail and cars, tie plates were often placed under the rail. These tie plates commonly had four holes for spikes, two on each side of the rail, so eight spikes per tie were used.

Now, some kind of plate or under support for the rail, sometimes with sound deadening qualities, is common in all types of rail fastening systems. By far one of the most common and popular fasteners, used with concrete and some composite ties, is the Pandrol ™ e-clip design. There is also a fast clip from the same manufacturer. Less common are tension clamps that are screwed into the tie using a heavy-duty screw, and simple bolt clamps that are not much more than a threaded rod embedded in (or threaded bolt holed through from underneath) the ties onto which a piece of bar stock serves as a giant rectangular washer topped with a nut that is clamped down on the rail base.

You may not see any nuts anywhere else. Rail joiner bars, and their nuts and bolts, are much fewer and far between on account of welded rails. These result in extremely long sections of track where the old clickety-clack of a passing train does not occur.

All of the above, then, allow the track to be assembled, either on site (with welded rail) or remotely in panels, and placed into position on the prepared grade. Once the track is in place and roughly positioned, ballast is applied. Ballast types vary by railroad and availability, but harder granitic rock types are preferred over limestone or softer or more abrasive types. Today’s practice is to fill ballast up to the top of the tie and leave little space below the rail base.

Last, but not least, proper tamping of the ballast assures that the rock is sufficiently confined but will yet allow proper drainage. Ideally, with a modern grade and installation, rain and snowmelt will flow away from the track center and never accumulate below it.

That’s it, with a few variations for bridges and tunnels, special trackwork (crossings and switches), and other areas, such as service pits. The variations often only involve heavier components, or more intensive use of each component in a given area.

Keep in mind that modern track installations are only a little more complicated than those of 100 years ago. What holds the track together is still ballast, ties, and a few roughly ¾-inch cross-section pieces of steel spikes or screws or studs embedded in the tie. That track like this held together in the past is a miracle of materials engineering, planning, and foresight. That it holds together under today’s heavy trains is also a bit of engineering science and a lot of experience, testing, and just plain hard work on the part of the railroads. When there are track failures, they are seldom in the way track is held together, but more often in the way it is used, inspected, or maintained; and the latter two are getting better all the time.

So, ultimately, the final answer to “What’s holding the track together?” is in the hands of the railroad that’s using it; and it may not be nuts and bolts, but people and the devotion to duty that is a railroad tradition.

©2017 – C. A. Turek – mistertrains@gmail.com

(Charles A. Turek is a writer and novelist based in Albuquerque, NM. After four decades working in areas of the insurance industry related to transportation, he now writes on all aspects of American railroading. Charles is a political conservative but believes in public funding of passenger rail as a part of the federal government’s constitutionally conservative obligation to provide for defense and public infrastructure so that private enterprise may flourish.)