Prototype…

Derby is a small community situated at the historic crossing of the Illinois Southern Railway and the Mississippi River & Bonne Terre line. After the two systems were merged, the M-I maintained a two-track yard here, recognizing the strategic importance of the junction. Derby served as a key interchange between the predominantly east–west Ste. Genevieve Subdivision and the largely north–south Bonne Terre (BT) Subdivision, which penetrated the Old Lead Belt.

Layout adaptation…

Derby Junction includes a run-around and a two-track yard that together form the southern terminus of operations on the layout. Were the railroad ever extended, the next point south would be Bismarck—eight miles farther—where the M-I interchanged with MoPac’s DeSoto Sub. For now, MoPac interchange traffic is set out at Derby, where it awaits pickup by the MoPac.

Operating sessions typically begin with northbound Local No. 92 staged at Derby Junction. The road crew reports for duty, gathers the interchange cuts, and begins sorting and switching according to the day’s traffic.

Interchange business at Derby includes lime products headed into the Old Lead Belt on the BT Sub and Illinois coal routed inbound from the north. The Valley Dolomite Company at Desloge ships high-quality dolomite to Illinois steel mills for use in blast-furnace flux. Additional traffic includes gondolas of chat from St. Joseph Lead Co. at Bonne Terre. Chat finds wide use—in concrete aggregate, roadstone, railroad ballast, and metallurgical fluxing—making it a steady, high-volume commodity.

Operators may spot the tan “mountain” on the backdrop: it represents the enormous chat pile near Flat River, rising more than 30 stories and visible for miles!