Mike, amend your roster to include X-83, the 3rd caboose. The windmill was a generator for generation of electricity for caboose lighting. This was a trait shared with the other Duke Power-owned shortline, the Piedmont & Northern. I'm not certain, but think X-84 was an X-P&N caboose. The hopper car fleet was not in captive service on the D&S, but was used to ship aggregate all over for owner (after Duke) Nello Teer Co. of Durham, NC, primarily a construction firm. The D&S served as a conduit for rock from a Nello Teer owned pit to Durham and the rest of the country. These cars were commonly interchanged to other area RR's and were seen throughout the region when the D&S was in existence. It would be more accurate to view the D&S hopper fleet as spice for your southeastern region RR freight. They were not "per diem" cars in the way we came to define that genre in the 70's, but they were seen all over in freights of the SCL, SR and N&W. It is this characteristic that makes these cars desirable for modelers of other than the D&S. You, however, need more than 3. <VBG> The NS cars (an even smaller group of 10 unmodified) were similarly seen on all area lines. They were primarily in sand and aggregate service out of the 2 Becker Sand & Gravel pits near Lillington, NC.