Pros
The checks don't bounce. The work is typically not super physically demanding.
Cons
Unions Pacific actively pursues policies that undermine employee's quality of life, especially in regards to work life balance. Union Pacific actively pursues policies that undermine employee's financial security. It is literally possible to be required to work so much that the government says you have to take days off, and in response the company docks your pay for having unscheduled days off. Management is a joke. Local level either doesn't know what you do or lacks the authority to make practical decisions to help you. Upper management is trying to squeeze blood from a stone to expand their already massive profits. There's never enough manpower or equipment to do the job properly.