OVERHEAD TRUCK LANES

March 1, 2004
To the editor:

Charles Potts, president of the National Asphalt Pavement Association, calls for dedicated truck lanes and improved intermodal transportation to ease major congestion, road repair, and safety problems on the Interstates. (Sun-Times, Feb. 28)

Why not put the truck lanes overhead? The chic catchphrase to the contrary, there is a technical solution, say, a new monorail technology. Its structure is a simple steel I-beam held overhead by heavy duty light poles every eighty feet or so. It blocks very little light, does not need another swath through city or countryside, and can use existing road or rail rights-of-way without disrupting near-by activity.

The vehicle underneath the beam is both propelled and suspended by a glorified clock motor, otherwise known as a linear induction motor. There is little more to a linear induction motor than the grade school experiment in which a kid wraps wire around a nail and makes an electromagnet. Such motors have long been used in industry to move metals directly, from powders to ingots, with induced currents and magnetic fields, without intervening machinery.
About 3/8" under a steel beam, it creates a magnetic force along the beam and about ten times as much toward it. Not being a pure maglev, this technology uses caster wheels over and under the flanges of the beam to keep it from falling or clamping up. Being suspended beneath the beam, the vehicle does not need elaborate, expensive structure or mechanisms to keep it from tipping. Do you carry a bucket of water from above or below?

A heavy duty version could get 40 ton trucks off the highway, while moving them much faster. The vehicle need only be the motor, automatic controls, and a clamp to pick up the trailer. It need only pick up the load and go, just like trucks, singly or in electronically spaced convoys. without being loaded into railroad cars, without time-consuming switching into trains.
The clamp could likewise pick up a skid that a bus could drive on and off, whether between cities or within metropolitan areas.

Such a monorail could be built over existing expressways and offer high speed service, freight and passenger, 150 mph or more, if desired. The Interstates are shorter and straighter than railroads built decades earlier. The conflicts with existing road and rail traffic that hamstring high speed rail simply do not exist.

At 150 mph, coast-to-coast would only take twenty hours.

The major freight markets, however, are less than 500 miles. As it happens, such short markets are largely the province of overnight trucking, rail being too slow and cumbersome. Thus drivers are forced into night jobs requiring them to sleep away from home half the time. The trucking industry is short several hundred thousand drivers; people simply do not want to be away from home like that anymore. Such a monorail could handle the intercity run two or three times faster than the highway and leave the driving to local pick-up and delivery.

The operating expense would be little more than electricity. Overnight power, of course, is much more easily and cheaply available than in peak periods.

William F. Wendt, Jr.