Dynamometers have been used extensively by design engineers and researchers to measure and enhance perfomance of all types of automotive, truck, aircraft and marine engines for decades. Yet, the first engine dyno (as it is more commonly known) was built in the mid-1890s for Purdue University at Lafayette, Indiana. Its purpose was to measure the output power of railroad steam engines, as well as electric interurban motor cars. Not-to-be-out-done, long-time rival University of Illinois also opened a locomotive test lab, in 1912.

Those early lab buildings were comparable in size to a one and a half-stall roundhouse with basement pit that contained large rollers located underneath the drive wheels of a locomotive; the locomotive chassis was anchored in-place to prevent movement. When conducting tests, the free-spinning rollers measured motive power output. On Purdue's experimental "Schenectady" (pictured at top), "The pull on the drawbar was measured by a weighed arm connected to a series of levers."

Recognizing the railroad industry's impact on the economic and social fabric of the U.S. other universities gradually entered the field. Rather than invest heavily in construction of a free-standing locomotive test facility, the newcomers opted to transform various types of railroad cars into rolling test laboratories. Penn State University was among the first to employ the innovative approach. Quick to recognize the advantage of a rolling laboratory, the University of Illinois and Purdue University also built test cars. It was not long afterwards that locomotive builders (and eventually railroads) began fashioning dynamometer cars that addressed their own specific requirements.

We'll take a closer look at the modern day dynamometer car in next month's profile.