@BatTrain: Yes, as Bill has stated it is 494 vibrator coil activated Beacon. Which replaced the 394 in 1954.
This particular item came along w/ “the large collection”, & is untouched by me (& just to mention: the vast majority of said collection was/ is in Very Good, to Excellent, to Like New condition. So having said that, it’s of no surprise that this beacon works like new.).
Now, for the potential tweaking of your beacon (assuming it is a 494): I have mine connected to dial power. I haven’t looked where I last set it at, but if I were to guess the voltage would be set around 10-12v, maybe even lower. If hooking yours up to dial power doesn’t help subside it’s stubbornness, then you may want to consider replacing it’s rubber fingered washer/ driving washer & adhesive washer. And if that doesn’t whip it into shape, the vibrator coil may indeed be faulty & need replacement as well.
One more thing to check, is that your center post base & ground terminal clips are secure, then perhaps the wiring to the coil itself.
Hope this helps you out, Sir.
And, Thanks so much for your compliment!!