Signalmen had to monitor whether the trains were on the right track
Okay, we know that signalmen still exist to this day. Yet, it is important to note that this job is definitely nothing like it used to be almost 200 years ago. In fact, there are some places in the world where computerized railways have almost fully replaced these workers.
Signalmen worked managing multiple switches and levers by hand to ensure that all trains were on the right track and that there were no accidents. Today’s signalmen, however, do not have to do anything similarly physical. They just have to sit at a control tower and press some buttons.