The cab layout you see here is typical of most of this railway's steam engines, going back to the late 1800s. Not much has changed. In some ways, it looks like any steam engine, with a firebox door, a water glass and injectors on both sides. But the similarities end there. Note that the big "Johnson Bar" which controls the valve gear on most normal steam locomotives is non-existent here. These engines have no valve gear. The cutoff is fixed at approximately 85%, which is a high-power setting. That can be a problem on shallower grades, when residual steam in the cylinders causes back-pressure on the pistons. Since the cutoff cannot be changed, there is something called a side-stack valve on the Engineer's side, which channels some of that exhaust steam away from the smokebox and up a separate exhaust pipe in front of the cab. This engine also does not have a conventional throttle. It has a big, Forward Steam valve where the throttle would normally be. This is the big wheel you see high above and just left of the Engineer's seat. An adjacent, smaller wheel opens and closes the Reverse Steam Valve.

This locomotive has 4 cylinders, but no driving wheels. The wheels on this engine are free-turning and simply support it on the rails. The two forward cylinders drive the forward cogwheel, through a series of reduction gears. This is indeed a geared locomotive. The rear set of cylinders similarly power the rear cog. Going forward, she runs like any steam engine and has a ratchet and pawl arrangement to prevent her from rolling backward during the climb to the summit. Going down hill, she uses good old gravity as a driving force, and the compression in her cylinders to manage the speed.....similar to the "Jake Brake" on a diesel truck. During descent, a small amount of water from the boiler and oil from the lubricator flows to the cylinders to keep them cool. The cylinder cocks are kept open, so the water is exhausted with each stroke. Finally, there is a giant hand-brake wheel sticking up out of the cab floor, immediately to the Engineer's left. A quick turn of that wheel and everything stops pretty quickly. A couple of other miscellaneous details include the massive water glass and an accompanying line of gauge cocks which help the crew keep track of the water level, which is critical, given that the grades vary from darn near level, to 37.4%. The crews have to know the line extremely well, and constantly anticipate where the water needs to be. Level ground is probably the most critical, because the down-angle of the boiler is the greatest in that condition. For this reason, the crown sheet on these boilers is deliberately set very low....just above the firebox door. In addition to the two injectors, this engine also has a feedwater pump, which is driven by a cogwheel under the tender. That is what feeds the boiler most of the time, with the injectors used to supplement that. This locomotive's tender carries approximately 1 ton of coal and 750 gallons of water and she'll use most of the coal and 1,000 gallons of water making the trip to the summit, which obviously means a stop for water about 1/3rd of the way up the hill.