Purchased by the Henderson Corporation in 1979, the W.D. Whinery company has 55 years experience in the alternating current/direct current (AC/DC) electrical bus systems, specializing on large systems with copper and aluminum mixes. Henderson Specialties Inc is a construction company, providing engineering and design services for over 150 years to the various parts of the United States and Mexico. The various services offered by the company include process engineering, electrical engineering, drafting and computer-aided design (CAD) services, facility and operations evaluations, damage appraisal and transportation specialist. The millwright division of Henderson Specialties Inc has a fleet of cranes and heavy hauling equipment to move and reinstall machinery. Lowboys, flat beds, and drop decks constitute the base of the firm s transportation fleet.