A former first sergeant with the US Marine Corps, Gary Garbrandt now works as a conductor for the Burlington Northern Santa Fe Railroad. In this capacity, he helps train crews connect cars, promotes the safety of bystanders and passengers, and inspects train equipment. Gary Garbrandt is also responsible for ensuring trains comply with railroad signals.
Railroad signals are often seen with three colored lights showing red, green, or yellow. When looking at these signals, each light governs a specific route. In most cases, the top light is the high-speed route that allows trains to travel at speeds above 45 miles per hour. High-speed routes are often straight ahead and do not require trains to go through any switches.
Meanwhile, the middle light governs the medium-speed route, which allows speeds of around 30 miles per hour, and the bottom light governs the slow-speed route. This latter route only allows speeds of up to 15 miles per hour.
When on a three-light signal, green means trains can proceed as normal because the tracks are clear for at least two blocks past the signal. Yellow means trains should proceed with caution because the track is only clear for one block beyond the signal; after the next signal, the route cannot be passed. Finally, red means a route is impassable.
Depending on the color and the location of the light, trains can see how they are supposed to move. For example, a green light on top, a red light in the middle, and a yellow light on bottom means that the high-speed route is clear for two blocks, the medium-speed route is impassable, and the slow-speed route is clear for one block.
