The Papers consist almost exclusively of drawings done by Henry T. Wilhelm, William Bruce Coughlin, and Richard C. Carpenter of main and branch line railroads and interlocking tower layouts, mainly in the United States and in particular in the regions that were represented in the first three volumes of Mr. Carpenter's work A Railroad Atlas of the United States in 1946. The materials created by Mr. Carpenter date from 1946 to 2001. The maps done by William Bruce Coughlin and Henry T. Wilhelm, were given to Mr. Carpenter by Mr. Wilhelm. These latter two collections contain similar drawings, dating from 1919 to the 1970s. A small number of the drawings were done by unknown others and were likely done as early as 1900.The papers also includes official railroad track charts and signal department drawings of signal interlocking towers. Mr. Carpenter notes that nearly all of the thousands of signal towers which existed in the United States have long since been abandoned, along with thousands of miles of track. Many official railroad records have been destroyed. Therefore, the drawings constitute a historic record of what was once an elaborate, complex and fascinating network of railroad tracks and signals.
