After that a better vestibule was devised by Col. W. D. Mann, one that extended the full width of the car. In fact the platform of the car had practically ceased to exist, the structure being full-framed to include its entrances at both ends.
After the vestibule came the steel car, introduced within the past ten years for freight service, and within the past five or six for passenger equipment. It has everything to commend it, save a slightly increased original cost, which is more than compensated by economy of maintenance, to say nothing of the intangible but certain raised factor of safety. It is to become universal; the wooden car will become extinct upon American railroads almost as soon as the present equipment is worn out and sent to the scrap-heap.
Of the forms and varieties of railroad passenger coaches there are many, and these will be described when we come to consider in a later chapter the luxury of modern railroad travel. But the variety of passenger equipment quite pales before that of the freight service. Flat-cars, coal-cars, box-cars, grain-cars, live-stock cars--the list runs on into catalogue form. There are refrigerator cars that are kept filled with salt and ice or ice alone, precooled cars that are merely kept air-tight, and ventilator cars employing a distinct reverse of that method; and up in northern climates there are heater-cars which are kept warm by lamps or by stoves and which are used for the transportation of fresh fruit and vegetables in winter just as the refrigerator-cars and the precooled cars are used for that same purpose in summer.
Almost all the safety devices that have been added to the running-gear of the passenger equipment have been added to the freight equipment also, to the great safety and peace of mind of the railroad employee. The car itself remains the simple essential of the very beginnings of the railroad. Its change has been a change in size, in weight, and in strength.
The first freight cars of the very old railroad at Mauch Chunk weighed 1,600 pounds each, and were permitted to carry a weight or "burden" of only 3,200 pounds. When the Boston & Albany first began using freight cars 30 feet long, it was so confused that it gave each end of the car a separate number for convenience in billing and designating consignments. Nowadays 40 tons is the right load for an efficient car, although they go as high as 55 and 60 tons' capacity; the car itself may weigh approximately half that figure.