With their own railroad ballasted long ago the Glenwood, South Park & Pacific let us loan their Ballast Car #15 for laying new track on our railroad.
It's a great piece of equipment for dumping large amounts of rock on unballasted track. For our own maintenance needs we built Ballast Car #103, which is much smaller and has square drop-down chutes that allow for better control of where the rock lands when it exits the car.
These two cars are rarely seen apart from one another even if one or the other is not in use.