I am in the process of constructing a 4X10 layout; HO scale, modern (or thereabouts) time period, Midwestern town. I am currently transferring my paper layout to the plywood and trying to orient structures, scenery and track together.
My question relates to how a hopper would dump its load. I am planning on having an asphalt plant (the Walthers Black Gold Asphalt Plant) on one end of the layout that will be served by a siding that will deliver gravel to the plant. With my current plan, the siding elevation works best with the rest of the layout if it is about 1.5" higher than the plant. I saw an article in a “how-to” book that showed how to build a gravel dumper, and this type of structure would fit nicely into my layout.
Is that how railroads really operate? I haven’t been able to come up with a kit or other information on putting something like this together, so any advice is welcome.
Prototype open-top cars that would ordinarily be used in gravel service unload through bottom drop doors, and a low-volume asphalt plant would not have a legitimate requirement for a tilt- or rotary dumper. In mild climate areas, the unloading facility is a pit under the track, served by a skip, belt or screw conveyor. Where the weather is more severe, the pit is frequently covered by a structure that will protect the machinery from precipitation and provide a place for thawing frozen lading. This is also done where it may be desirable to protect the product being handled from airborne pollutants (Santa-Ana-borne dust would not improve the quality of pelletized plastic!)
For modeling, you can spot a car with a removable load, then pop it out by hand (to be reused) before pulling the empty.
What’s your time period? Until the cost of manual labor really started to rise in the 1960s, most small industries that only needed a single occasional hopper load of minerals (coal, sand, gravel, etc) actually just dumped the load right onto the siding, and hired a bunch of guys to shovel it into waiting wheelbarrows or flatbed trucks. It sounds VERY strange to us living in 2006, but that’s how it was done at virtually every small town across America.
I’d suggest you look at some coal yards for direction. Most had an elevated track of varying height - usually 4-8 feet so the coal could flow into a bin underneath. Since they stocked different sizes several drop points with dividing walls were under the track. Sloan Blabon shingle company in Philadelphia received granules for shingles and they dumped into a pit with a bucket conveyer to move them to the plant. the picture I have is mid 1950’s so whichever works for your situation.