The updates are coming slowly as the engine is now in a very tedious process: plumbing!
Meanwhile, let’s take a look at the engine’s air compressor.
The 9″ steam operated air compressor was manufactured by Westinghouse. It’s mounted on the left “non-park” side so at the park it can only be seen while the engine is at Main Street Station. The compressor takes steam from the steam manifold in the cab, and uses this steam to drive a piston, which compresses air in the cylinder at the bottom of the compressor. The compressed air is stored in two air tanks. The main air tank is at the rear of the pilot truck (immediately front of the running gear hardware). The second air tank is under the cab, rear of the driver.
The main air tank has several connections. It has: (1) the feed/supply pipe from the compressor; (2) the connection to the air brake control; (3) the safety valve; (4) the compressor bypass and valve; and (5), the pressure gauge piping. That’s quite a bit of connection piping for such a little tank.
The second tank is used as the equalizing reservoir.
Here’s an old diagram of the system, similar to what is installed on the engine. Steve informed me that the diagram shows an automatic type, while the engine uses a straight air type. As such, the engine and the model will not have the aux reservoir and the triple valve.
And here’s the air compressor model. It’s been modified since this rendering.
The top cylinder is the steam cylinder. It has a half-cylinder protecting jacket (much like the boiler jacket but without a lagging–only air space). The manufacturer build plate is mounted on the jacket.
The bottom cylinder is the air cylinder, where the piston compresses the atmospheric air. The cone is air filter for the compressor intake.
Two different condensation drain lines are shown coming from the steam cylinder and supply.