What is the plan to make the murder of Phyllis husband to appear to be an accidental fall from a train that will trigger the "double indemnity" clause and pay out twice the policy's face value.

After Dietrichson breaks his leg, Phyllis drives him to the train station for his trip to Palo Alto for a college reunion. Neff is hiding in the backseat and kills Dietrichson when Phyllis turns onto a deserted side street. Then, Neff boards the train posing as Dietrichson and using his crutches. He makes his way to the last car, the observation car, and steps outside to the open platform to supposedly smoke a cigarette. A complication ensues when he meets a passenger named Jackson (Porter Hall) there, but he manages to get the man to leave. Neff then throws the crutches on the railway tracks, jumps off at a prearranged meeting spot with Phyllis, and drags Dietrichson's body onto the tracks by his crutches.