¹ Railway Age 1 (II November 1876): 441. No reliable source of statistics showing the number of passenger cars with air brakes prior to 1888 has been found, but evidence from a variety of sources suggests that the switch to air brakes was virtually complete by 1877. That year the Massachusetts railroad commissioners declared the change complete in that state, and discussion of air brakes in railroad trade journals of that and subsequent years centered on maintenance, not on the initial adoption of the device. The earliest reliable national statistics show that by 1889, 7,706 of the nation's 8,079 passenger locomotives (92 percent) and 23,540 of its 25,665 passenger cars (95 percent) were equipped with automatic air brakes. Some of the cars and locomotives without the automatic brake were outfitted with an earlier, nonautomatic version of the air brake. A few isolated roads may still have relied on hand brakes. See United States Interstate Commerce Commission, Statistics of Railways in the United States (hereafter, ICC Statistics), 1889.

² In 1889, less than 8 percent of the nation's freight cars were equipped with automatic air brakes, according to ICC Statistics, 1889.

³ Little is known of the invention and early refinement of the air brake. The following brief account is based on Westinghouse, George, “Conception, Introduction, and Development of the Air Brake,” Santa Fe Employees Magazine 5 (September 1911): 35–43Google Scholar; Leupp, Francis E., George Westinghouse: His Life and Achievements (Boston, 1918)Google Scholar; Prout, Henry G., A Life of George Westinghouse (New York, 1922)Google Scholar; and articles in Railroad Gazette.

⁴ The automatic air brake used compressed air both to keep the brakes off when the train was moving and to power the brakes during stops. When an engineer wished to stop, he released air from the “train pipe,” and this reduction in pressure enabled air to flow from reservoirs into brake cylinders on each car, setting the brakes. A novel “triple valve” mediated these functions. The brake was automatic because if a train split, air escaped from the train pipe, and the brakes came on automatically. Before Westinghouse added the triple valve and the reservoirs, an increase of air pressure in the train pipe powered the brakes directly, and if a train broke in two the brakes could not be activated. Not all railroads went directly from hand brakes to air brakes. A few, such as the Pennsylvania, employed a chain brake on passenger trains. The chain brake enabled engineers to set brakes on short trains directly from the cab of the locomotive, but the brakes on each car had to be reset by hand before the train could resume motion.

⁵ Westinghouse, 36–38, and Leupp, 64–72. The reaction of the Pennsylvania's executives to the demonstration of the air brake on their line can be found on microfilm roll 10, Board Papers, Pennsylvania Railroad Company, accession 1807, Eleutherian Mills Historical Library, Wilmington, Delaware.

⁶ On these patent policies, see Prout, 25 and Railroad Gazette 8 (21 April 1876): 163. On the vacuum brake, see Railroad Gazette 5 (17 May 1873): 197; 6 (19 September 1874): 365; 7 (6 February 1875): 36; 7 (15 May 1875): 192; 8 (14 April 1876): 159–161; and 8 (21 April 1876): 176; and Reports of the Proceedings of the Master Car-Builders' Association (hereafter, MCBA Reports), 1875.

⁷ This impression of the railroad safety movement emerges from a reading of the New York Times and of railroad trade journals of the period. Clark, Charles Hugh, “The Railroad Safety Movement in the United States, 1869 to 1893” (Ph.D. diss., University of Illinois, 1966)Google Scholar, sees the concern with safety on freight trains growing out of the invention of the air brake, not preceeding the invention as in the passenger case.

⁸ Railroad Gazette 10 (23 August 1878): 417. The comment echoed an earlier one that appeared in MCBA Reports, 1875. See also, Railway Age 3 (29 August 1878): 427; and Westinghouse, “Conception.”

⁹ MCBA Reports, 1885, indicate that railroads owned over 800,000 freight cars. ICC Statistics list slightly over one million freight cars in 1889 and nearly 1.3 million in 1894.

¹⁰ The standard source on these developments is Taylor, George Rogers and Neu, Irene D., The American Railroad Network, 1861–1890 (Cambridge, Mass., 1956).CrossRefGoogle Scholar

¹¹ New York Times, 21 March 1879.

¹² Taylor and Neu. The western companies had a further advantage because their common ownership tied them together and facilitated simultaneous action of the air brake and other aspects of the interchange-ability issue.

¹³ Railroad Gazette 15 (24 August 1883): 564; and 15 (2 February 1883): 80; and Westinghouse, 40. The western companies adopting the air brake included the Central Pacific, Union Pacific, Santa Fe, and Northern Pacific. On the refinement for mountainous routes, see Blaine, David G., “The Importance of Being Able to Stop,” Trains 35 (October 1975): 44–53.Google Scholar

¹⁴ William Forsyth to Godfrey W. Rhodes, 31 May 1884; W.A. Merrill to Harlan B. Stone, 28 May 1884; T. J. Potter to Stone, 28 June 1884; and Stone to Potter, 5 July 1884; Air Brake File, Archives of the Chicago, Burlington, and Quincy Railroad (hereafter, Burlington Archives). These records are located at the Newberry Library, Chicago.

¹⁵ Westinghouse Air Brake Company to Chicago, Burlington, and Quincy Railroad, 21 November 1883; Air Brake File, Burlington Archives.

¹⁶ Rhodes to Stone, 31 May 1884; this letter and the many testimonies Rhodes solicited from his subordinates can be found in the Air Brake File, Burlington Archives.

¹⁷ Westinghouse Air Brake Company to Chicago, Burlington, and Quincy Railroad, 21 November 1883; Rhodes to Stone, 31 May 1884; Rhodes to Stone, 18 June 1884; Air Brake File, Burlington Archives.

¹⁸ Potter to Stone, 28 June 1884; Rhodes to Stone, 2 July 1884; Rhodes to Stone, 23 May 1884; Stone to Potter, 25 May 1884; Air Brake File, Burlington Archives.

¹⁹ Rhodes to Stone, 31 May 1884; Stone to Potter, 19 June 1884; Air Brake File, Burlington Archives.

²⁰ This discussion of the debate over the benefits of increased speed is based on a variety of letters in the Air Brake File, Burlington Archives; on MCBA Reports, 1875–88; and on assorted articles in Railroad Gazette and Railway Age. In his important study of technological innovation and productivity in the railroad industry, Albert Fishlow demonstrates that air brakes provided significantly lower gains in productivity than other innovations (such as steel rails). Fishlow further suggests that railroads acted rationally when they delayed equipping freight trains with air brakes. This analysis may be correct in hindsight, but both the public and private discussions among railroad managers indicate that at the time of the innovation these managers did not fully understand the economic effects the adoption of air brakes would produce. The process of innovation in the case of air brakes for freight trains cannot be interpreted simply in economic terms. Fishlow, Albert, “Productivity and Technological Change in the Railroad Sector, 1840–1910,” in National Bureau of Economic Research, Output, Employment and Productivity in the United States after 1800 (New York, 1966): 583–646.Google Scholar

²¹ Stone to Potter, 19 June 1884, Air Brake File, Burlington Archives.

²² Potter to Stone, 28 June 1884; Stone to Potter, 4 April 1885; and George Westinghouse, Jr., to Potter, 1 April 1885; Air Brake File, Burlington Archives.

²³ Potter to Stone, 28 June 1884; and Stone to Potter, 5 July 1884; Air Brake File, Burlington Archives. Rhodes assumed the chairmanship of the committee; Railroad Gazette 16 (14 November 1884): 816.

²⁴ MCBA Reports, 1867–1884.

²⁵ Railroad Gazette 15 (30 March 1883): 191; and 16 (18 April 1884): 293; and MCBA Reports, 1884.

²⁶ MCBA Reports, 1875–1884.

²⁷ MCBA Reports, 1867.

²⁸ Printed circular from the Committee on the Reorganization of the Master Car-Builders' Association and letter from Stone to Potter, 17 April 1882; Burlington Archives. See also MCBA Reports, 1882.

²⁹ Railroad Gazette 16 (14 November 1884): 816.

³⁰ MCBA Reports, 1880.

³¹ References to new continuous brakes appeared with increasing frequency in railroad trade journals in the 1880s. Some of the new brakes were altered forms of air or vacuum brakes, and Westinghouse sued their manufacturers for infringement. Others used chains to connect the brakes or transmitted the braking power through the car couplers. None of the new brakes seriously challenged Westinghouse air brakes.

³² MCBA Reports, 1884. The Pennsylvania Railroad had purchased air brakes for freight cars used to transport livestock (a valuable cargo); MCBA Reports, 1882; and Potter to Stone, 28 June 1884, Air Brake File, Burlington Archives.

³³ Stone to Potter, 27 January 1886, Air Brake File, Burlington Archives. This file contains letters about shocks from the general superintendents of the Union Pacific and the Southern Pacific and from the general manager of the Santa Fe.

³⁴ This paragraph is based on articles appearing in Railroad Gazette from June to December, 1885. Railroad Gazette is the best source of information on the Burlington trials. The magazine closely monitored the activities of the MCBA committee on continuous brakes, sent representatives to the trials, and helped publicize all aspects of the tests. Useful information can also be found in Railway Age and the MCBA Reports.

³⁵ Railroad Gazette, December 1885 to February 1886; 18 (7 May 1886): 309; and 18 (18 June 1886): 426.

³⁶ MCBA Reports, 1887; and Railroad Gazette, July to September, 1886.

³⁷ Railroad Gazette, August and November, 1886. On the automatic coupler, see Clark, Charles H., “The Development of the Semi-Automatic Freight-Car Coupler, 1863–1893,” Technology and Culture 13 (1972): 170–208.CrossRefGoogle Scholar

³⁸ Railroad Gazette 18 (30 July 1886): 521–23. The slow activation of the air brake resulted because air drained only from the front of the train pipe, and the reduction in pressure that activated the brakes reached the rear of the train long after pressure had dropped at the front of the train.

³⁹ Railroad Gazette 19 (7 January 1887): 3.

⁴⁰ Railroad Gazette and Railway Age, April to June, 1887; and MCBA Reports, 1887.

⁴¹ Railroad Gazette 19 (17 October 1887): 653; and 19 (11 November 1887): 729, 734. Westinghouse achieved this quicker action by enlarging the train pipe and altering the triple valve. The larger pipe transmitted a shock wave the entire length of the train almost immediately after the engineer turned his brake lever to an emergency position. This wave triggered the altered triple valve, which vented air directly from the train pipe into the brake cylinder on each car.

⁴² MCBA Reports, 1888; and Railroad Gazette 20 (15 June 1888): 390.

⁴³ Railroad Gazette 19 (11 November 1887): 729, 734.

⁴⁴ Railroad Gazette 26 (26 October 1894): 740–41.

⁴⁵ Railroad Gazette 20 (1 June 1888): 346.

⁴⁶ Railroad Gazette 23 (27 March 1891): 215. On these instruction cars, see “Air Brake Instruction Cars,” Santa Fe Employees’ Magazine 1 (July 1907): 197.

⁴⁷ The application of air brakes to freight trains following the Burlington trials can be followed in ICC Statistics, 1889–1901.

⁴⁸ ICC Reports, 1893; and Railroad Gazette 20 (12 October 1888): 671; and 22 (21 March 1890): 197.

⁴⁹ Clark, “The Railroad Safety Movement,” provides an overview of the events that led to legislation. The best sources on the legislative process are the hearings Congress held on the proposed laws and ICC Reports, 1889–93.

⁵⁰ U.S. Senate, Reports from the Committee on Interstate Commerce, 52d Cong., 1st sess., Rep. 1049, 1–5.

⁵¹ ICC Reports, 1889, 338–39.

⁵² The transcripts of these hearings can be found in U.S. House of Representatives, Miscellaneous Documents, 51st Cong.., 1st sess., Rep. 142 and 145; U.S. House of Representatives, 52d Cong., 1st sess., Rep. 1678; and U.S. Senate, Reports from the Committee on Interstate Commerce, 52d Cong., 1st sess., Rep. 1049. Additional examples of railroad opposition to safety legislation appear in Railroad Gazette, 1887–93.

⁵³ The response to the Safety Appliance Act can be followed in the ICC Reports, 1893–1900. In asking for an extension of the Act, many railroads complained that the depression of the mid-1890s had prevented them from purchasing air brakes for freight trains.

⁵⁴ Constant, Edward W. has noted this uncertainty over economic factors in the generalized model of technological change presented in his The Origins of the Turbojet Revolution (Baltimore, 1980Google Scholar).

⁵⁵ Sinclair first explored the question of standards in his “At the Turn of a Screw: William Sellers, the Franklin Institute, and a Standard American Thread,” Technology and Culture 10 (January 1969): 20–34, and has recently expanded his analysis of the standards-setting process in his A Centennial History of the American Society of Mechanical Engineers, 1880–1980 (Toronto, 1980)Google Scholar.

⁵⁶ In this regard, it is interesting to note that when George Westinghouse reflected on the development of the air brake, he stressed that he had succeeded in large part because he had understood from the beginning that uniformity was essential. His early correspondence with the Pennsylvania Railroad about using air brakes in passenger service exhibits this concern (see microfilm roll 10, Board Papers, Pennsylvania Railroad Company, Accession 1807, Eleutherian Mills Historical Library). Despite his comprehension of the importance of uniformity, however, Westinghouse had to wait for the railroads to develop mechanisms for guaranteeing uniformity before he sold many air brakes for use on freight trains.

⁵⁷ The standard source on these developments, of course, is the work of Chandler, Alfred D. Jr. See especially his The Visible Hand: The Managerial Revolution in American Business (Cambridge, Mass., 1977).Google Scholar