Assertion: railway's locomotive | /r/CapableOf | permit gravity
Facets:
value: to keep the boiler
type: PURPOSE
Source sentences:
text: The early locomotives - represented today by the restored display locomotive, #1 Old Peppersass - all had vertical boilers, like many stationary steam engines of the time; the boilers were mounted to the locomotives' frames with twin trunnions, allowing them to pivot as the locomotive and coach climbed the grade, permitting gravity to always keep the boiler vertically oriented, no matter what the gradient of the track.