My Washington contact has informed me as to the route chosen.

3 seconds sound clip from Superman (1948) - Superman To The Rescue (Chapter 8).

You can hear this line at 00:07:03.874 in the Blu-ray version of the episode.

Quote context

[...]

- We know the Spider Lady is determined to get it, but we don't know her whereabouts. This is a chance to bring her into the open.

- At the risk of losing the reducer ray?

- We won't lose it, I promise. But it may enable us to capture the Spider Lady and Dr. Hackett.

- Well... If it were anyone else, I would say no. But we have absolute faith and confidence in you, so it's in your hands.

- All public traffic will be detoured from the route on the day that the invaluable reducer ray will be moved from Washington.

- 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.

[...]