as a former block operator on the NEC its a good job. as in every job on the railroad you start on the extra board. you will HAVE to qualify at your 1st tower and will move to another to qualify,. unless your working.its not centralized. the extra board is based on seniority. the senior person gets the pick of jobs first, the lowest man takes whats left. open jobs will be posted and you can apply, even if your not qualified at that tower
your job is to operate signals & switches for trains & track equipment according to the schedule, and whatever the train dispatcher wants. after a year as a qualified block operator, you can be promoted to a train dispatcher. the training isnt easy you will have to learn ton's of rules, the territory in your block. and like engineers & conductors you will be tested on the rules every year