Dear Kyle,

You are a really observant and bright 4-year old! Not many people would know that freight trains used to have cabooses at their back end. Long ago, it took a lot of people working together to run a train properly including the engineer, the fireman, the brakemen and the conductor. The engineer and fireman controlled the locomotive. Brakemen checked on all of the cars in the middle of the train. The conductor kept track of all the cars: he knew where the train was supposed to go, and where certain cars would leave the train and when new cars would be added to the train. The caboose, located at the end of the train, allowed the conductor to see the entire train. It also served as an office for all of the workers.

One of the most interesting jobs for these people was the starting or stopping of the train. A typical train has a lot of cars, and it is impossible to start or stop all of the cars at the same time. To get a train started, the engineer makes the locomotive move forward gently. The car behind the locomotive will not move until the slack in the coupler holding the two cars together is taken out. By this time, the locomotive has got a running start, and its momentum can help start the car behind it. After those two cars get moving, slack in the coupler to the third car is taken up and the chain reaction continues all the way to the caboose. Only after the conductor had signaled the engineer that the caboose was rolling would the engineer increase the speed of the train.

The back of the caboose was also a good place to put safety signal lights – like the lights on the back of your parent’s car. Years ago this was done with a lantern that was kept lighted by the conductor.

Over time, the jobs of the conductor and brakemen have been replaced by electronics mounted in a metal box attached to the last car of the train. This control box, called an “end of train device” or EDT, sends information about train motion and safety, to a central office location. Many of these boxes also have flashing lights that help others on the track see the end of the train. We sometimes call these boxes “FRED,” which means “flashing rear end device.”

Electrical engineers help design these electronic boxes that monitor the brake lines and detect train motion. Electrical engineers also design the radio systems that are used by trains to communicate with each other. Modern locomotives use huge electric motors to turn their wheels, and electrical engineers design control systems to make everything work well.

Thanks for your question,
Aubie and Dr. Hung