Snowpiercer Season 4 Episode 9 Dominant Traits ( Air Date 2024-09-15 ) Genre Sci-Fi & Fantasy, Drama category. Overview "Alex sabotages the track switch computer and, with Layton's help, escapes to town hall. Till gets the drop on Ace and uses his sniper rifle to save Layton and Alex from Rat. Melanie reveals the identity of Alex's biological father.".