Summit switching. Engineer Mark "Cookie" Sodergren coaxes his train slowly across the massive hydraulic switch just below the summit of Mt. Washington, in preparation for its arrival on the platform at New England's highest railway station. Just behind his train, we can see portions of the Mt. Washington Auto Road, and in the distance, way down yonder in Pinkham Notch, we see the Wildcat Ski Area, which from personal experience, seems to be one of the coldest places on the planet.
For much of its existence, the Mt. Washington Cog Railway was a single-track line from bottom to top. There were no sidings, no switches and definitely no passing. Trains traveled to the top in gaggles, and scheduling options were very limited. Typically, a gaggle of trains would go up in the morning, and another at mid-afternoon. In the modern tourist era, that scheme would prove very inefficient and unworkable.
Around 1941, a couple of sidings were added at Waumbek Tank and Skyline, to allow down-mountain trains to give way to up-mountain trains, and permit much more flexibility in terms of scheduling. In order to facilitate this, switches had to be developed, and with that center cog rail, they became the most complicated switches in all of railroading. There were 9 separate components and the process of setting them was a bit like some of the complex puzzles that are presented to contestants on the TV show "Survivor." The Conductors required a lot of physical strength to manipulate them, and the potential for error was high. Most Conductors would stand and stare at them for several seconds after setting these switches, just to ensure they were properly configured. The consequences of doing it incorrectly were high. The only fatal accident the railroad ever had with paying passengers was due to an improperly set switch.
Today, all of the "Survivor Puzzles" are gone. The last such switch was at Skyline siding, and it disappeared half a dozen years ago, along with the siding itself. All switches are now hydraulically-actuated and much more simple in configuration. In the scene above, we see MWRC #2 "Ammonoosuc" negotiating the summit switch, which selects the platform track on which the train will park. Trains remaining on the summit, such as the steamer, will park on one track, while trains that are only stopping to discharge and pick up passengers will park on the other. The switch is basically a sliding table, which contains two track sections, one of which goes left, and the other goes right. The table is moved with hydraulic actuators. Little electrical boxes on poles at cab-level, allow the Engineers to move the table to one side or the other, selecting the correct track. Movement over these switches is always done at a very slow speed, to ensure that there are no problems.