Complex sentence: The SLA was an automatic switching device mounted in a 10 ton trailer that allowed the PTS to remain connected to all three launchers allowing all three to remain hot and greatly decreasing the time between launches.
Split into simpler sentences: The SLA was an automatic switching device mounted in a 10 ton trailer that allowed the PTS to remain connected to all three launchers. This allowed all three launchers to remain "hot" and greatly decreasing the time between launches.