Operations during this busy period were complicated by the single 7800 foot passing siding, located at Alcoa, and also by the presence of the Watson and Malabar Roadswitchers, which worked around Malabar and between Watson and El Segundo during most of the day. Though the local jobs tried to clear the main line for passing through trains, often the through trains had to wait while complicated switching moves were completed around Alcoa. Other than the short sidings at Lairport and Ironsides, and the long siding at Alcoa, the line was completely single-track without signals, with the exception of those at the crossing of the Southern Pacific Wilmington Line at Slauson Junction, or at the ends of the Harbor Subdivision at Harbor Junction (downtown Los Angeles) or West Thenard (Wilmington). The lack of signals were accommodated by using Track Warrant Control over the district, as described in the next section.