Page:Popular Science Monthly Volume 90.djvu/208

 The Road-Rail and Its New Truck

��our highways

���A LARGE part of the cost of maintain- ing improved roads is due to heavy motor traffic. Motor trucks and motor omnibuses carrying loads of five to ten tons at speeds reaching fifteen to twenty miles per hour now run over roads improved at large expense, and cause great damage. State highway authorities all over the country recognize this as a most serious threat to the permanence of their highways.

To meet the situation, in part at least, Mr. Charles Whiting Baker, a well-known New York engineer, has designed a trans- portation system which carries its load on a smooth steel rail and which furnishes at the same time a permanent and durable auto- mobile highway at low cost.

The roadway consists of smooth Portland cement concrete. In the center of the road- way th^re is embedded a single line of steel rail, the head of the rail flush with the sur- face of the road, so that it does not inter- fere at all with the use of the road by auto- mobiles or horse-drawn vehicles.

The cars which run on this rail have double-flanged wheels running on the rail and they are kept balanced over the rail by ordinary vehicle wheels which run on the concrete roadway on either side. The cars are built with a low floor, only a few inches above the road surface, and the weight of the car and its load is thus

��A section of the economical roadway. It is of smooth Portland cement with a single rail em- bedded in the center and flush with the road surface. About ninety per cent of the weight of heavy trucks is carried on this rail

brought down so low that the load on the

balancing wheels to keep the car steady is very small. Not more than ten per cent of the car's weight is carried on the balancing wheels, so that even if the car with its load weighed as much as fifteen tons, the weight carried by the balancing wheels would be no greater than that carried by the wheels of an ordinary light touring automobile.

To propel the car there is at one end a gasoline engine, about the size of that used on an ordinary touring car, direct connected to an electric generator. On the trucks of the car are electric motors, which, by a sprocket-chain transmission, drive the car wheels on the rail. Suitable controllers distribute the current generated on the car to the motors on the trucks. The whole equipment is, in fact, similar to (but of smaller size than) that used on railway gasoline-electric cars, a large number of which are in successful operation in various sections of the country.

As the car is very light compared with an ordinary railway car and is designed for low speed operation, the power required to drive it is small. The cost of building this kind of a roadway may be varied within wide limits according to the character and volume of the traffic carried. A concrete road suffers practically no wear from the traffic of pneumatic-tired vehicles. What causes the wear is the grinding action of steel tires of heavy wagons. The monorail in the concrete roadway is designed to relieve the road of the burden of such trucks and thus lengthen the life of the highway and recluce the cost of its maintenance.

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