Covered hoppers can be unloaded in a variety of ways, most relying on gravity to move the cargo through the bottom outlets. The outlets can dump into a bin below the tracks; into the receiving opening of a auger unloader; or into a receiving transfer arrangement into highway trucks or trackside bins. All these method may rely in part on auger components, simply a screw rotating inside a tube, as shown below. Naturally rotation of the screw moves material along the tube.
Car unloading can involve simply dumping into a pit below the tracks, and the mechanism for moving the cargo from the pit can be anything from an auger to a conveyor belt (below ground, of course). Thus a grid or array of bars between the rails can be a complete unloading arrangement if desired (and if the destination is into a structure). It might look like this:
But there are also a variety of ways that an auger mechanism can be arranged and be evident from above. One of these is with a portable auger, than can be moved from car to car, for example unloading into trucks. These can be quite steep, more so than a conveyor belt:
But what I want to do on my layout is indicate an unloading spot, and rather than just make a dump pit, I want to indicate directly that there is an auger mechanism. My idea to do this was inspired by a Clark Propst clinic about his own layout, in which he showed a photo of such an auger in a 1949 photo of a cement company, with the receiving bin visible above the auger in the track. Clark was kind enough to send me a copy of the photo, which looks like this:
The unloading spot is quite narrow and the means of connecting the car unloading gate to the auger box is evident. Here is that area, expanded from the photo above:
Note that there is a flat top to the device, but that the round auger tube underneath can be seen, as can the shaft end of the auger itself.
I am going to try and model this, and will take up that project in a following post.