Wikipedia states that steam engines were fitted with centrifugal governor to keep a rotational speed almost constant.

For steam locomotives, Wikipedia speaks about regulator but nothing about the automation of this regulator. I imagine this device is less needed in the case of a locomotive because of the greater moving mass. Nevertheless, automating the locomotive speed regulation might be useful. That way, there is less risk of over-speed in case of unexpected sliding (traction control?) or when the track goes downward.

Was there any steam locomotive fitted with a centrifugal governor or any other device whose purpose was to control steam flow based on locomotive speed without human intervention?

  • $\begingroup$ Which steam locomotive? There aremany and most have sufficient documentation that can be checked. $\endgroup$
    – Solar Mike
    Commented Jul 7, 2020 at 7:48
  • $\begingroup$ The speed governor of a locomotive wasn't centrifugal. He usually wore a fancy hat though. $\endgroup$
    – SF.
    Commented Jul 7, 2020 at 11:35
  • $\begingroup$ More typical of a stationary steam engine ; Source of the phrase "balls out" indicating the governor weights were at the maximum speed position. $\endgroup$ Commented Jul 7, 2020 at 14:55
  • $\begingroup$ @SolarMike I didn't find any source speaking of centrifugal governor fitted on any steam locomotive (hence the formulation of the last sentence of the question). If you have any resources I didn't find that states that there is at least one type of steam locomotive fitted with such device, you should write an answer. $\endgroup$
    – Manu H
    Commented Jul 7, 2020 at 16:41
  • $\begingroup$ So you want me to research this? $\endgroup$
    – Solar Mike
    Commented Jul 7, 2020 at 16:42

1 Answer 1


A governor is a poor application for steam locomotives because the throttle is constantly adjusted by the driver. Speeds, loads, and steam pressure change constantly, plus a major part of driving a train is managing slack in the cars. Even today, managing slack is done by the engineer using the throttle. All this means that an engineer would spend more time adjusting the governor than would be required to just open or shut the throttle.

Stationary steam engines generally had pressure-controlled steam supplies and were much more of a constant speed engine. The throttle would not need to be staffed 100% of the time, so a governor is of great use.


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