Steamfitters local250 in Los Angeles has jurisdiction for all southern California, shortline and longlines(mainline) including all stations(compressor, heater,etc.). 798's jurisdiction extends to most of the country but the states that do have thier own jurisdiction often have it for mainlines aswell. but most steamfitter/pipefitter locals dont have the welders to man these jobs. also, a mainline can kickoff in 798's jurisdiction and end up in another locals jurisdiction and still 798 will control all that work due to the fact that the perponderance(majority) of the work started with them so that it is theirs to do. national mainline agreements can pertain to any local that has the work.