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?