Snoqualmie Depot with its Train Order Board.
The Snoqualmie Depot is a wonderful example of Victorian architecture. Hanging from the front of the depot is a strange metal sign that appears more decorative than functional. Yet this bowtie is a signal, an important one from the days before radios and telephones.
When trains first started operating, keeping space between different trains was important. It was rare for railroads to have the ability to build two tracks to keep trains running in both directions. This meant trains had to follow a strict schedule to prevent collisions.
The Train Order Board in “Proceed” aspect. The board is parallel to the tracks and displays green lights.
American railroads initially used a Timetable system, where trains are scheduled and listed in a chart with arrival and departure times for each station. This worked well at first but was inflexible. With the introduction of reliable telegraph machines in 1844, railroad dispatchers could keep track of trains along the railroad and create extra trains. Extra trains are trains that are not a part of a timetable, like an extra freight train or a late train. Dispatchers could also contact stations and relay orders to be passed up to a train when schedules changed.
The Train Order Board in “Stop” aspect. The board is perpendicular to the track, visible to trains, and displays red lights.
To let crews know there were new orders, stations began carrying train order signals using physical boards for daylight and lights for nighttime. Early signals had only two aspects, “Proceed” and “Stop” with corresponding green and red lights. Later signals carried an additional yellow aspect called “Permissive.” This told crews to be ready to pick up orders while moving. Older signals could be modified to show a “Permissive” aspect with the addition of a yellow board or lantern.
The Train Order Board in “Permissive” aspect. A yellow board is now hanging from the board, which would be replaced by a yellow lantern at night.
Snoqualmie Depot’s train order board does not date from its opening. It was installed later by the Northern Pacific. Though the signal is operable, it is only used for demonstrations.
