The vastness of the railroad industry may be imagined when one considers that from fifteen to twenty per cent of the capital of the United States is invested in railroads. As an exhibit of the growth and importance let me quote the following statistics of railroad growth by decades since the first operation:
| 1830 | 23 | Miles |
| 1840 | 2,814 | " |
| 1850 | 9,021 | " |
| 1860 | 30,635 | " |
| 1870 | 52,914 | " |
| 1880 | 93,296 | " |
| 1890 | 163,597 | " |
| 1900 | 193,346 | " |
| 1909 | about 250,000 | " |
Such is the exhibit of progress in the extent of railroads, broadly viewed. With the growth in extent the elements of safety have multiplied and have become very numerous; in fact, an almost indefinite subdivision of railroad property and operation in respect of safety might be conceived. We will consider, however, the beginnings and the growth of a few of the more important and striking items and their relationship to the state of the art, as portraying in a more graphic manner the adjustment, if you may call it such, of safety to progress, or, as the subject has been assigned to me, "Progressive Safety."
AIR BRAKES.
As the density of traffic, and the speed, together with the weight of equipment, developed, following upon the greater transportation to be undertaken, the question of brakes was an important factor. More efficient brakes were needed; the essential characteristics being that they should be continuous throughout the length of the train, simultaneously applied and released, with a single point of control.
In 1869 George Westinghouse, Jr., brought forth what is known as the straight air brake, consisting of a pump, main reservoir, three-way valve, brake cylinder and train line. Application was made by admitting air from the main reservoir into the train line. The brakes were released by reducing the train-line pressure into the atmosphere through the three-way valve. The brakes were useless if there was a leak, a burst in the air line or a parted train.
With these shortcomings in mind, the automatic air brake was produced in 1873, in which the method was reversed. With the addition of an auxiliary reservoir under each passenger car and a triple valve, application of brakes was secured by reducing the train-line pressure, while admitting air from the main reservoir raised the pressure and released the brakes. On the application of the automatic air brake to freight cars it was found the reduction of pressure was not quick enough to set the rear brakes promptly, and in consequence accidents occurred from the bunching of the cars.
The consideration of the brake question by the Master Car Builders' Association in 1885, and public tests under their auspices in 1886, at which time the manufacturers were represented, did not succeed in stopping freight trains without violent and disastrous shocks. So discouraging did these tests seem for the time being, that a report was made, suggesting that the successful application of such brakes on long trains could only be accomplished by electricity. However, the following January witnessed the introduction of the Westinghouse Quick-Action air brake, which corrected the previous trouble and made practicable the application of air brakes to long freight trains. Continuing from this time there has been marked improvement and development in all features of the apparatus, without, however, modifying the essential elements of which it is constituted.
With the solution of a means of train control came a further growth in their size and weight; sooner or later this had to emphasize the necessity for efficient coupling devices. Not only were there accidents due to the primitive link and pin couplers, but the various standards in existence both complicated the operations of coupling and uncoupling of cars and involved the question of interchange and safety.
AUTOMATIC COUPLERS.