On June 1st the USMRR reported 88 box cars and 79 flat cars, with no passenger or stock cars at Aquia Creek. This data will help me size my car fleet. It will be a shame to not have any stock cars on the layout, so I may freelance that a bit, but note that stock cars comprised only 1 percent of the fleet. I do find it odd that I have a picture showing a conductors car in use as a telegraph hut at Stoneman's Station, but these reports make no mention of conductors cars until September.
In the similar report for September 1863, there is a new class of cars listed, cabooses (see the highlighted section of the report). The word caboose has also been added to the box car roster shown below. These are the only occurrences of the word "caboose" I have so far seen in a civil war era documents . Has anyone else seen this term used in the ACW?
Also note that 16 box cars were used as offices and 2 for hospitals.
Finally, the next three documents will very important to the freight car builder as they list the road numbers for each type of car in service on the USMRR at the time of the report. These essentially form a roster of equipment, although the exact types of car are not listed. There are more pages available, but this should help you if you need to accurately number your freight car models. Click for larger images.