[Illustration: Figure 14.--THE "FURY," BUILT FOR THE Boston and Worcester Railroad in 1849 by Wilmarth. It was known as a "Shanghai" because of its great height. (Smithsonian Chaney photo 6443.)] [Illustration: Figure 15.--THE "NEPTUNE," BUILT FOR THE Boston and Worcester in 1847 by Hinkley and Drury. Note the similarity of this engine and the _Fury_.] [Illustration: Figure 16.--THE "PIONEER" AS FIRST EXHIBITED in the Arts and Industries building of the Smithsonian Institution prior to restoration of the sandbox. (Smithsonian photo 48069D.)] The steam dome (fig. 18) is located directly over the firebox, inside the cab. It is lagged and jacketed in an identical manner to the boiler. The shell of the dome is of 5/16-inch wrought iron, the top cap is a cast-iron plate which also serves as a manhole cover offering access to the boiler's interior for inspection and repair. [Illustration: Figure 17.--"PIONEER" locomotive. (Drawing by J. H. White.)] [Illustration: Figure 18.--"PIONEER" LOCOMOTIVE, (1) Safety valve, (2) spring balance, (3) steam jet, (4) dry pipe, (5) throttle lever, (6) throttle, (7) crown bar, (8) front tube sheet, (9) check valve, (10) top rail, (11) rear-boiler bracket, (12) pedestal, (13) rocker bearing, (14) damper, (15) grate, (16) bottom rail, (17) pump heater valve, (18) cylinder lubricator, (19) reversing lever, (20) brake shoe, (21) mud ring, (22) blowoff cock, (23) ashpan. (Drawing by J. H. White.)] A round plate, 20 inches in diameter, riveted on the forward end of the boiler, just behind the bell stand, was found when the old jacket was removed in May 1963. The size and shape of the hole, which the plate covers, indicate that a steam dome or manhole was located at this point. It is possible that this was the original location of the steam dome since many builders in the early 1850's preferred to mount the dome forward of the firebox. This was done in the belief that there was less danger of priming because the water was less agitated forward of the firebox.