to the public, museum officials used compressed air to power the cylinders and move the wheels through the connecting rods for the first time since its last semi-operation. After the compressed air blew some dirt and debris out of the locomotive's exhaust stack, it was soon running smoothly. The running gear seemed to be in good order, but it was still not known whether the boiler could still handle the pressure of steam and a live fire again. The museum asked the Hartford Steam Boiler Inspection and Insurance Company to inspect the locomotive's boiler for operation. The inspections were conducted after hours at the museum (from 6:30 p.m. to 4:00 a.m.) over three days and included electromagnetic, ultrasonic, and radiographic tests. The tests did reveal a few flaws, but it was projected that the engine could operate at a reduced boiler pressure of 50 psi (340 kPa); as delivered to the Camden & Amboy, the boiler was rated for . The Smithsonian's staff, after a few further hydrostatic tests, were confident that the locomotive could again operate under its own power. The items that needed repair were serviced, and on October 14, 1980, the locomotive was successfully field-tested on the Warrenton Branch Line in Fauquier County between Calverton and Casanova, Virginia. The site was selected because at the time only one freight train per week used the branch line. On September 15, 1981, the locomotive operated under steam on a few miles of branch line near the Potomac River within Washington, D.C. With this exhibition, the locomotive became the oldest operable steam locomotive (and oldest self-propelled vehicle) in the world. , the original John Bull was on static display in the Smithsonian's National Museum of American History and the replica was preserved at the Railroad Museum of Pennsylvania. Timeline June 18, 1831: The John Bull is built by Stephenson and Company in Britain. July 14, 1831: The John Bull departs Liverpool aboard the ship Allegheny bound for Philadelphia, Pennsylvania. September 4, 1831: The John Bull arrives in Philadelphia. September 15, 1831: The John Bull makes its first runs in New Jersey under its own power. November 12, 1831: Robert Stevens hosts a group of New Jersey politicians on a series of trial runs pulled by the John Bull. 1833: The John Bull is one of a few locomotives operating on the newly completed Camden and Amboy Railroad. 1866: The John