A lot of people complain that driving across the United States is boring. Having done the coast-to-coast trip seven times now, I can’t agree. Sure, the stretches through the Corn Belt get a little monotonous, but for someone like me who wants to know how everything works, even endless agriculture is fascinating; I love me some center-pivot irrigation.
One thing that has always attracted my attention while on these long road trips is the weigh stations that pop up along the way, particularly when you transition from one state to another. Maybe it’s just getting a chance to look at something other than wheat, but weigh stations are interesting in their own right because of everything that’s going on in these massive roadside plazas. Gone are the days of a simple pull-off with a mechanical scale that was closed far more often than it was open. Today’s weigh stations are critical infrastructure installations that are bristling with sensors to provide a multi-modal insight into the state of the trucks — and drivers — plying our increasingly crowded highways.
Trains are one of the oldest and most reliable ways we have of transporting things and people over long distances. But how often do you think about trains? Where I live, they can clearly be heard every hour or so. I should be used to the sound of them by now, but I like it enough to stop what I’m doing and listen to the whistles almost every time. In the early morning quiet, I can even hear the dull roar as it rumbles down the track.
I recently got a front row seat at a railroad crossing, and as the train chugged through the intersection, I found myself wondering for the hundredth time what all the cars had in them. And then, as I have for the last twenty or thirty years, I wondered why I never see a caboose anymore. I figured it was high time to answer both questions.
Boxcars are probably the most easily identifiable after the engine and the caboose.
Boxcars carry crated and palletized freight like paper, lumber, packaged goods, and even boxes. Refrigerated box cars carry everything from produce to frozen foods.
Boxcars (and barns for that matter) are traditionally a rusty red color because there were few paint options in the late 1800s, and iron-rich dirt-based paint was dirt cheap.
Standard, no-frills flat cars are the oldest types of rail cars. These are just big, flat platform cars that can carry anything from pipe, rail, and steel beams to tractors and military vehicles.
Flat cars come in different lengths and are also made with and without bulkheads that help keep the cargo in place. Some flat cars have a depression in the middle for really tall or heavy loads, like electrical transformers.
As the name implies, auto racks carry passenger cars, trucks, and SUV from factories to distributors. They come in two- and three-level models, although there have been specialized auto racks over the years.
Perhaps the strangest auto rack of them all was the Vert-a-Pac. When Chevrolet came up with the Vega in the gas-conscious 1970s, they wanted to be able to move them as cheaply as possible, so they shipped the cars on end. If you’re wondering about all the fluids in the car when they were upended, a special baffle kept oil from leaking out, the batteries were capped, and the windshield washer fluid bottle was positioned at an angle.
The power grid is a complicated beast, regardless of where you live. Power plants have to send energy to all of their clients at a constant frequency and voltage (regardless of the demand at any one time), and to do that they need a wide array of equipment. From transformers and voltage regulators to line reactors and capacitors, breakers and fuses, and solid-state and specialized mechanical relays, almost every branch of engineering can be found in the power grid. Of course, we shouldn’t leave out the most obvious part of the grid: the wires that actually form the grid itself.
In a bout of frustration I recently realized that the roads have all updated — most people have no idea how — and this sometimes hurts the flow of traffic. This realization happened when an unfortunate person stopped in a left turn lane well before the stop line. The vehicle didn’t trigger the sensor, so cycle after cycle went by and the traffic system never gave the left turn lane a green light, thinking the lane was unoccupied. Had the driver known about this the world would have been a better place. The first step in intelligent automation is sensing, and there are a variety of methods used to sense traffic’s flow.
Traffic lights are so ubiquitous that we hardly give them a second thought, except to curse their existence when they impede us on our daily drive. But no matter how much it seems like traffic lights have the ability to read our minds and tell when we’re running late, they’re really not much more than a set of lights and a programmable controller. Simple in practice, but as usual, the devil is in the details, and for a system that needs to work as close to 100% of the time as possible, the details are important. Let’s explore the inner workings of traffic signals.
Electromechanical Timing
The traffic lights and crosswalk signals at an intersection are only the public user interface, of course. The interesting stuff is going on in the control box. There’s at least one at every intersection, usually a plain metal cabinet set back from the road, sometimes camouflaged with public bills or graffiti. But inside are the guts of what makes an intersection work and keeps vehicle and foot traffic moving smoothly and safely.
Unsurprisingly, most traffic signal controls started out as purely electromechanical devices. Cabinets were chock full of synchronous motors turning timing wheels with cams to cycle the intersection’s lights through the proper sequence. One old time controller that was common up until recently was made by Econolite, and the insides are a paragon of sturdy design.
The need for clear and reliable communication has driven technology forward for centuries. The longer communication’s reach, the smaller the world becomes. When it comes to cell phones, seamless network coverage and low power draw are the ideals that continually spawn R&D and the eventual deployment of new equipment.
Almost all of us carry a cell phone these days. It takes a lot of infrastructure to support them, whether or not we use them as phones. The most recognizable part of that infrastructure is the communications tower. But what do you know about them?
