Weaver 2-8-0 noise

I recently picked up this nice looking Weaver 2-8-0 engine. It runs smoothly, but has a very annoying high pitched whine as well as a grinding sound that I tried to capture in the video. Is this a normal sound for these engines ? I took the shell off and found several loose screws (not including mine LOL ) and tightened them. Nothing looked like it was rubbing. It has the normal looking DC motor connected to the gear with a plastic piece connecting the 2 parts. The whine is the most annoying. You can hear it above the sound of 12 scale freight cars running on the tracks. The grinding I'm not too fond of, but I bought a new MTH UP Golden Spike 4-4-0 a while back and it runs great, but has a similar grinding sound. Both engines have a louder sound going forward and slightly quieter sound going in reverse. Anyway, I bought the Weaver based on a couple of great reviews from people on here. Just want to know if something is wrong or this is how they sound. Thanks. - Scott