Was the signalman’s job tough or demanding?

What we see from the text is that the signalman's job is not demanding in a physical sense. However, it is tough and demanding from a mental perspective. For a start, this job does not involve any contact with the outside world, making it a very isolating occupation. The narrator, for example, talks about those "many long and lonely hours."
Although the signalman has grown accustomed to the loneliness of his post, he feels burdened by the "exactness" and "watchfulness" which is required of him. He is constantly listening out for the "electric bell," for instance.
In addition, from the signalman's experiences, we see that he is the first person on the scene when a train accident occurs. This can be a very distressing experience for the signalman. He can hear the "terrible screams and cries" of the passengers, for instance, and has to deal with the casualties. After one accident, he had to take the body of a "beautiful young lady" to his signal box while help arrived.
So, while the signalman's job is not physically demanding, it is clear that it takes a heavy toll on his mental health.