Fellow ACWRR modeler Marshall Stull alerted me to the following document that contains several interesting items for 19th century railroads. Fourth Annual Catalog of Locomotives and Car Builders Supplies. It has a bunch of interesting drawings in it, especially of tools and surveying equipment.
One item in particular caught my eye, this railroad track scale. It looks like an interesting item to add to a layout.
Note the operator using a switch stand to move the rails from through route to the weighing tracks.
It is unlikely that the USMRR had one on the Aquia line, but any commercial railroad would need these at several locations.
Note the floor depot scale at the bottom, another useful detail one could add.