Editing Dynamometer car (section)

== Usage ==
While the principal purpose of the dynamometer car was to measure the power output of locomotive, other data were typically collected, such as smoke box data, throttle settings and valve cut offs, fuel burn rates, and water usage to determine the overall performance and efficiency of the locomotive.

Data would typically be recorded on time-indexed continuous paper recording rolls for the pull and velocity.  Power would later be manually calculated from these data on early cars. Some later cars were equipped with a mechanical [[integrator]] to directly record the power.<ref name=Hay />

A separate use for the car was to test a particular rail route to rate it for tonnage based on a run with a dynamometer car and recording the effect of the grades and curvature on the capacity and resulting power requirements for that line.<ref name=Hay />