One of the early problems in transportation was to secure the carrying capacity of cars as well as safety. We have pointed out how it was necessary to add a guiding truck to the English locomotive, designed to adapt the same locomotive safely to American conditions. Both the excessive wheel loads on four-wheel freight cars and the greater liability to accident or derailment led at an early time to the use of four-wheel trucks under cars. Between 1831 and 1834 Mr. Ross Winans, of Baltimore, made improvements on cars on the Baltimore & Ohio Railroad. He applied the swivel four-wheel truck, the outside bearing for axles, and the application of the draft gear to the car body and not to the trucks. The increase in lengths of passenger cars, with corresponding increases in weight, led, about 1880, to the quite general employment of a six-wheel truck instead of a four-wheel truck, and even eight-wheel trucks were used for a time, but rejected on account of the excessive length of wheel base and other complications.
In 1879 the Allen wheel, consisting of built-up construction with forged-steel tire, was introduced and rapidly became applied to cars in the most exacting service. Originally the tires were imported from the Krupp Works, in Germany, but later were manufactured here.
Great interest attaches itself at the present time to the manufacture of solid-steel forged wheels, on account of the reduction in parts.
In the latter '80s experiments were made in the development of steel framing for car construction, and built-up steel underframes were introduced shortly after; at first on cars for mineral traffic, where excessive weights and capacities were required. The success of this type of construction has led to its adaptation at the present time to all classes of equipment, and not only steel underframes, but complete steel construction in certain classes of service where the conditions require.
With the increase in through passenger service we note the appearance of the vestibule, protecting the communication between cars. Originally this vestibule was narrow, about the width of the car door, and was introduced about 1882, although experimented with as far back as 1845. The equipment of the "Exposition Flyer," operated from New York to Chicago during the World's Fair, was the first, we believe, to appear with full-width vestibules, these being originally designed as offering less atmospheric resistance to high-speed trains, but having subsequently been found a more economical, attractive and safer form of construction.
The question of steel cars and composite steel and wooden cars is having very careful investigation and experiment at the present time. While considerably used, the results of the use of these cars must be awaited. After the factor of safety has been determined the question of tare weight per passenger carried will naturally arise. In this country our weights are now far in excess of all foreign railroad practice. This enters into the resistance and cost to produce the service.
CAR HEATING.
The original method of heating passenger cars by direct radiation from coal or wood stoves was a source of discomfort to the passengers as well as a menace in case of disaster. This brought about in the late '80s the introduction of the "Baker Hot-Water Heater," which was a great improvement for the comfort of passengers, but still left a fire in the car. In many instances of collisions and derailments during this period, especially in winter, the cars were set on fire and the wreckage consumed from the fire scattered from the stoves or heaters. Experimentally, steam from the locomotives was used, but the difficulties in securing satisfactory couplings between the cars, the drain on the boiler, and the fact that the locomotive was sometimes detached from the train, were obstacles. One of the Western roads even attached a separate car for the sole purpose of supplying heat and light. The growth in the capacity of locomotive boilers, and the perfection of the couplings between cars, have led to the present practice of car heating, which entirely eliminates the presence of any fire or source of danger from that source.
CAR LIGHTING.
Car lighting has passed through the same stages as house lighting, possibly more gradually, on account of the greater difficulties. The old low-roofed passenger cars were illuminated by candles about two inches in diameter, placed in racks along the sides of the car. With the advent of mineral oil, just before the Civil War, the candles gave place to oil lamps. Great difficulty was experienced in maintaining a steady flame, until the principle of the student lamp was adopted. The flame was shielded from the outside air by a chimney, and the central draft to the burner provided the air necessary, at the right point, to insure combustion. For more than fifteen years this method prevailed, and while the presence of oil lamps in wrecks contributed fuel to the flames, the proof that they were in any way the principal cause was lacking. Still, to eliminate this contributory feature, attempts were made to use ordinary coal gas, compressed in tanks on each car. This, however, proved unsatisfactory. In 1870 a system of compressed gas made from crude petroleum had been invented by Julius Pintsch, of Berlin, and by 1887 had been put into a number of cars on European railroads. The light was too dim to satisfy American conditions. It was only a question of time, however, for its proper and adequate development to our needs, when its use became general, on the perfection of the lamp and burner.