Pennsylvania Railroad class A3
The A3 was an 0-4-0 class steam locomotive that were built and operated by the Pennsylvania Railroad. These locomotives were built by Pennsylvania Railroad's Altoona Shops from 1895 until 1905. A3s were used to shunt and sort out railroad cars at various Pennsylvania Railroad yards. Later some A3s were converted to A3a, which had saddle tanks. The A3 was retired by 1920s when the railroad introduced the much stronger A5s. Today, none of the A3 locomotives survive.