I want to know about American pay system.
if a man gets a job as flagman and continues to be flagman after 10 years, is his pay he receives from the company almost same or some differences? does he receive pay as contractual bases?

In Korea we are employed as life-time basis. So we will retire at 58 yrs old.
How about in America?

If he promotes to a conductor or engineer, is there big differences?

I am working for Korean National Railroads.