This is great. I studied FEM in school and got my first job in industry as a structural analyst. I started my own firm when I was 25 and employed 22 analysts that I contracted to Pontiac Motors.
I worked as a structural analyst on passenger train cars (metros, LRVs, etc) for a while, as my first job after grad school actually.
Depending on the project (client requirements), we designed for 25-35 year lifetimes, with 12-24h operation typical. That usually amounted to millions of kilometers.
We had load cases with varying numbers of cycles. Eg curves with light loading might have been millions of cycles, but max (or even over max) loading might have been 10s or 100s of thousands of cycles.
All load cases were determined based on on usage stats from the operator and testing conducted to measure accelerations on the operator's infrastructure.