Alfred Wolcott Gibbs (October 27, 1856 – May 19, 1922) was a mechanical engineer in the railroad industry who attained the position of chief mechanical engineer of the Pennsylvania Railroad.[1][2] He was instrumental in the design of a number of important PRR locomotive classes, including the E6 4-4-2 "Atlantic" type, the K4s 4-6-2 "Pacific" type, and the L1s 2-8-2 "Mikado" type.