HOW IT ALL WORKS - All Aboard: The Complete North American Train Travel Guide - page 163

For years, individual rails have been 39 feet long—not really
an odd number, since they were originally hauled on standard
40-foot flatcars. They're laid end to end and bolted together
at the joints. It's this joint that makes the clickety-clack sound
when the car's wheels pass over it. Today, when track has to be
replaced, quarter-mile lengths of welded rail are most often used.
It goes down much faster, and because the joints are some 1,300
feet apart and are welded together, the clickety-clack sound is
gone. That, of course, is how you can tell when your train passes
onto a stretch of welded rail.
The rails themselves vary in size, weighing anywhere from
112 to 145 pounds per yard. The size of the rail used depends on
the amount, weight, and speed of traffic it's going to get. Heavy-
duty rails are found on main lines, with lighter-weight track used
for spurs and sidings.
You'll probably notice track work going on in many loca-
tions during your train trips. The equipment used is fascinating
to watch. One machine (actually, it's several machines mounted
on a number of articulated railcars) will remove the old wooden
ties, level the ballast rock, put new concrete ties into position,
and install welded rail—all in one operation. In fact, as this
incredible machine is functioning, the front part is rolling on the
old rails, while the rear is actually riding on the new rails it has
just installed.
It's also amazing to remember that for years, railroad work-
ers laid track using only hand tools. Incidentally, back in the late
1800s, most of those tools were made by the Gandy Manufactur-
ing Company. The word Gandy was stamped on the handle of
every pick, shovel, and hammer. That's why, even today, track
workers are still called gandy dancers .
Every so often you may see one or more of the wooden cross
ties smeared with white paint. That means those ties have either
been marked for replacement or for treatment with a chemical