There has been greater interest in railroad technologies than in aspects of economic development and regulation. A centerpiece has been the development of steam locomotives, arguably the most fascinating piece of machinery ever created. Several works offer a basic understanding of this long-lasting source of train propulsion: Alfred W. Bruce’s The Steam Locomotive in America; John H. White’s American Locomotives: An Engineering History, 1830–1880; J. Parker Lamb’s Perfecting the America Steam Locomotive; and William L. Withuhn’s American Steam Locomotives. Studies of diesel-electric locomotives, the replacement technology for steam, are less common, but Franklin M. Reck’s The Dilworth Story: The Biography of Richard Dilworth, Pioneer Developer of the Diesel Locomotive; Lamb’s Evolution of the American Diesel Locomotive; and Wallace W. Abbey’s The Diesel That Did It offer insights into the development of this motive power. Also useful are Albert J. Churella’s From Steam to Diesel and Jeffrey W. Schramm’s Out of Steam: Dieselization and American Railroads, 1920–1940. Occasionally, steam roads, most famously the Pennsylvania Railroad and the Milwaukee Road, electrified portions of their lines. William D. Middleton examines this technology in the revised second edition of When the Steam Railroads Electrified. Rolling stock has not been slighted. White covers passenger equipment in his encyclopedic The American Railroad Passenger Car. He also considers the lowly freight car in another comprehensive work, The American Railroad Freight Car.
Three aspects of railroad technology in the nineteenth century encompass track gauge, bridge building, and time zones. By the immediate post-Civil War years, standardized track widths (four feet, eight-and-a-half inches) had become largely universal, but a short-lived narrow-gauge craze erupted nationwide. Thousands of miles of line were built to three or three-and-a-half feet. Promoters mistakenly believed that a reduced gauge would be less expensive to construct and to operate. For more than a decade beginning in the early 1870s, companies were organized to install slim-width tracks. Except for scattered remnants, largely in California and Colorado, most narrow-gauge trackage had been widened to standard gauge by the 1890s. Two studies tell much of the narrow-gauge saga: George W. Hilton’s American Narrow Gauge Railroads and Bruce A. MacGregor’s The Birth of California Narrow Gauge.
When much of America’s railroads were built, civil engineers or others with similar skills needed to develop ways of making grades as low as possible, necessitating the occasional tunnel. To manage thousands of water crossings, including some of the continent’s great rivers, bridges were mandatory. For the longer spans there would be the transition from wood and stone to iron and then to steel by the 1870s. A landmark bridge connected East St. Louis, Illinois, with St. Louis, Missouri. This was the Eads Bridge, opened in 1874, and the subject of Rails across the Mississippi: A History of the St. Louis Bridge by Robert W. Jackson. Middleton wrote a complementary study, Landmarks on the Iron Road: Two Centuries of North American Engineering.
Prior to the early 1880s travelers experienced a so-called time problem. With the advent of longer rail journeys, each railroad embraced its own notion of what would be the correct clock setting, often using the time of whichever city its headquarters principal terminal was located. This resulted in a crazy-quilt pattern of dozens of times determined by the position of the noonday sun. A union station served by multiple carriers required more than a single clock. However, American ingenuity came to the rescue. What was known as the General Time Convention, composed largely of railroad officials, solved this conundrum. Railroads established four zones that ran roughly along the 75th, 90th, 105th, and 120th meridians, and implemented these demarcations on November 18, 1883, the day of two noons. Ian R. Bartky, the preeminent authority on matters of time, explores this topic in Selling the True Time: Nineteenth Century Timekeeping in America.
Other technologies that involved American railroading in the twentieth century are numerous. The evolution from telegraphy to telephony for business communications and especially for train controls is obvious. Then there are the diesel-powered streamliners that made their debut in the mid-1930s and new methods that proved better for transporting freight shipment. Two of these methods—trailers-on-flatcars (“piggybacks”) and containers-on-flatcars (“boxes”)—proved revolutionary as components of intermodal movements. The former became popular in the mid-1950s and the latter in the 1980s, including the ubiquitous “double stack” containers. Leading studies include David J. DeBoer’s Piggyback and Containers: A History of Rail Intermodal on America’s Steel Highway, Solomon’s Intermodal Railroading, and Marc Levinson’s The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger.
When the Steam Railroads Electrified, Revised Second Edition by 
