Dowling & Kennedy were railroad contractors. The partnership of Dowling & Kennedy and its predecessor, Reynolds, Dowling & Company, were typical of the many small firms that subcontracted to grade sections of railroad rights of way for large general contractors. This collection contains account books, vouchers, and statements covering the receipt of monies from the general contractor and its expenditure for labor and supplies. There are also timebooks, payrolls, and correspondence.

The Mount Carbon Railroad Company was incorporated in Pennsylvania on April 20, 1829, for the purpose of building a railroad from the Schuylkill Canal at Mount Carbon up Norwegian Creek to the forks and thence to Wadesville on the East Branch and Mount Laffee on the West Branch. The collection consist of thirteen laborers receipts issued for the construction of the railroad in 1829 and 1830 by William R. Hopkins, superintendent.

The Phoenix Iron Company began in the late eighteenth century as a manufacturer of cut nails. It later became a major producer of railroad rails and iron and steel structural members. This small collection of records includes incoming correspondence chiefly relating to orders for and deliveries of iron for railroads.

The Phoenix Steel Company began in the late eighteenth century as a manufacturer of cut nails. It later became a major producer of railroad rails and iron and steel structural members. Their records include minutes (1856-1929); stock ledgers; brief of title papers and property maps; legal and financial correspondence and tax papers; account books; and a works diary.

The Taylor-Wharton Iron & Steel Company produced frogs, switches and other railroad fittings including couplings, axles and wheels, as well as war material during both World Wars. The company was incorporated in 1912 as successor to the Taylor Iron & Steel Company. The collection contains photographs primarily of products such as dredging equipment, railroad tracks, rollers, crushers, and buckets. The films document dredge buckets in operation and were shot in the United States and at international locations. The collection has been organized into four series: Company history, Plant views, Products, and Films. Each series is arranged alphabetically.