People are also leaving because the schedules they have to keep are unpredictable and horrible. My brother-in-law worked for a bit as an engineer, and as a person low on the totem pole, got bad assignments (all of the more senior people took the decent ones) and often didn't have a schedule until a day or two before the train was scheduled to leave. It hurt his social life substantially, because he couldn't plan on anything. Then COVID hit, and even though the company has hurting for people to run the trains, he was furloughed "until further notice" with no potential return date. Honestly, the companies are doing this to themselves with poor management.