IF YOU WANT TO SEE NINETEENTH-CENTURY technology still hard at work today, just go stand by the nearest railroad crossing and watch the past roll by. Not that you’ll see steam locomotives and antique rolling stock; most of the equipment on today’s railroads is quite up-to-date. But the industrial style and culture of the railroads have changed remarkably little in the past hundred years. Railroad technology was the centerpiece of the nineteenth-century Industrial Revolution, and it still is.

The basic idea of railroading is steel wheels on steel rails. Compared with rubber tires on a concrete roadway, this metal-to-metal contact allows heavier loads to be carried with less friction. Reduced friction makes for greater energy efficiency, but it has other consequences as well, not all of which are entirely welcome. For one thing, less friction means the driving wheels can’t get much of a grip on the rails, so trains have only limited acceleration. You’ll never see a locomotive make a drag-race start. And for the same reason, trains don’t stop very well. The engineer’s nightmare is seeing a catastrophe waiting to happen a mile up the track, and knowing the train can’t be stopped before getting there.

Running on rails has another obvious effect: You don’t have to steer. In fact, you can’t steer, even if you want to. The train’s motion is one-dimensional; it goes wherever the track goes. The switching point where one track branches away from another may look something like a highway exit ramp, but it works differently. On the highway, it’s the driver who decides whether to go straight or turn off, but on rails it’s the switch in the track that makes the decision.

More than other modes of transport, railroads attract amateur enthusiasts and collectors of lore and memorabilia. Some of these “railfans” have nostalgic or antiquarian interests, commonly focused on the Age of Steam or the era of luxury passenger trains in the 1920s and 1930s. Others are fascinated by modern train operations; they monitor railroad radio frequencies and keep life lists of locomotives spotted, in the manner of bird-watchers. The information collected in this chapter does not reach the level of detail that would satisfy a railfan. My aim is merely to present some of the commonplace elements of railroad infrastructure.