@dkdkrd wrote:
I recall another source said they had better success attaching the finger washer to the inside of the beacon instead of to the top surface of the solenoid. Haven't done this myself, but maybe worth a try.
Per Olsen's Train Repair Database CD, for the 494 beacon, an adhesive washer is first installed in the Lens Bracket, followed by a driving washer with the nibs facing outward from the Lens Bracket, and these nibs sit on the base's coil.