Erwin and Jackson will stop the truck.
2 seconds sound clip from Superman (1948) - Superman To The Rescue (Chapter 8).
You can hear this line at 00:07:13.967 in the Blu-ray version of the episode.
Quote context
[...]
- It is rumored that Superman will guard the ray machine.
- My Washington contact has informed me as to the route chosen.
- But what good will that do us if it's so closely guarded?
- My men will be there before the area is closed.
- Erwin and Jackson will stop the truck.
- How do you know the ray machine will be in a truck?
- I have definite information.
- But what if Superman is there?
- You and Brock will take care of Superman with Dr. Hackett's new weapon, if it's finished in time.
- It will be. You needn't worry about Superman.
- Now we'll work out the details.
- I want all men to be at their stations before that truck leaves Washington.
- Get up the other road and watch for the truck.
[...]