from The Century Dictionary and Cyclopedia
- n. A tip-car or flat-car used to transport loose gravel. Such cars are sometimes fitted with a double mold-board plow, on a guide-rail, which, when the train is at rest can be drawn, by means of a steel rope wound by the engine, over the cars, thus discharging the gravel on each side. See car-unloader.
Sorry, no etymologies found.
Once start this gravel-car and she'll go clear to the hills.
And the gravel-car crept along as if it would stop any moment.
A day would come when a splendid passenger - train would glide smoothly down this easy grade where Casey jolted along on his gravel-car.