Really you need to talk to people.
Like the law, the actual implementation of a contract depends on the company, union, and precedent. Often they are intentionally written to be extremely hard to understand and ambiguous to interpretation.
There are some contract comparison docs floating around for the majors right now (many are in negotiations). These docs provide a side-by-side apples-to-apples comparison of key contract provisions. I suspect there's something like that at one or more regionals too.