UP 5118, looking sharp in fresh paint, leads a westbound local off the ACTA Alameda Corridor Subdivision and onto one of the outside leads adjacent to the Alameda Corridor as an Amtrak Pacific Surfliner sits at the entrance to the trench. Wait...that's not right, is it? You read that right - for four (4) days in December of 2023, Metrolink shut down all operations - mainly due to station work in and around Los Angeles Union Station. Since a majority of the work took place on the west bank of the Los Angeles River near Mission Tower, the Los Angeles-San Diego-San Luis Obispo (LOSSAN) agency in charge of Pacific Surfliner operations opted to continue operating Surfliners by having them bypass LA Union Station. This was accomplished by using tracks on the east bank of the LA River, which are generally used by Metrolink and Union Pacific trains and not Amtrak. As such, when northbound Amtrak trains from San Diego came into Vernon, they would travel on BNSF tracks that merged into the ACTA Alameda Corridor Subdivision at the mouth of "The Trench." From there, crews would switch ends and then take the train back east to cross the river again before banking north along the river to continue their journey.