I doubt that anyone in UP management cares one way or the other about illegal aliens. Railroads out of necessity don't hire people who cannot pass a background check and prove who they are (or do they?), so the crowd that ICE is trying to round up aren't UP employees. But UP has a visible presence in places like the Bay Area, Portland, Chicago and so on and probably don't want to give the woke mob any reason to turn the riots on them.