What happened to the people who died building the transcontinental railroad?

I know a lot of the workers were Chinese and Irish immigrants, and a lot of them didn’t have clear documentation of their lives or deaths. I’m wondering if there are any records whatsoever of where they buried people who died building the railroads? Were any records kept of who they employed? I know we’ve been able to uncover graves from a few specific incidents of mass casualty, but outside of that I haven’t been able to find anything. I have an ancestor who might’ve died out there and I’d love to be able to find some record of him but besides a couple pictures of people on the job, which don’t even list their names, I haven’t found anything showing all those people even existed. Surely there were some documents somewhere where they wrote down who they hired, that researchers might be able to use to figure out who ended up where?