Arriving at Marshfield Station. In this elevated view, we see Mt. Washington Railway #2 "Ammonoosuc" descending with her coach on the last few feet of track above the platform area at the station named for Cog Railway builder, Sylvester Marsh.
Descending trains are typically photographed much less often than ascending ones, because they are much less spectacular-looking, but this operation is actually pretty interesting. First and foremost, the locomotive and coach are actually descending separately. The locomotive is braking using cylinder compression, not unlike the "Jake Brakes" that are used on diesel trucks. A small amount of steam is continually released into the cylinders to cool and lubricate them, as compressing air generates a lot of heat. The Engineer, who is not visible in this photo, manages the mechanics of the descent, while the Fireman who is visible standing in the cab, typically keeps watch on the track, especially that vital center cog rail. The coach is descending using disk-type brakes mounted on its wheels. The Brakeman, who is clearly visible in the window next to the locomotive, has two, large brake wheels on the back wall of the coach, which he/she manipulates to wind the brakes, with the goal of keeping the coach just barely touching the locomotive. If something were to happen to the steam engine, that Brakeman can make the descent just as well without it.
Astute observers may note the presence of a large gear engaging the cog rail under the tender. This is not one of the power cogs that the engine uses to claw its way up the mountain. Rather, that gear actually powers a feedwater pump in the tender and is part of the feedwater heater system which is located on the left side of the locomotive. Note also that no coal is visible in the tender. While there is some small supply left after each trip, the vast majority of the one-ton load is used to make the 3-mile ascent to the summit. The tender also holds about 700 gallons of water, but ascent requires about 1,000 gallons, hence the need for a water stop at Waumbek Tank, about 1/3 of the way to the top.