Reliable affordable engine for 031 curves (and a follow-up thank you to Marios Trains)

Got my order from Mario's today.  He sent me the wrong diesel which I am sure will be corrected, but my main question is about the 4-6-0 Williams (Bachmann) steamer.

In forward only it makes a kind of high pitched buzzing sound.  I have heard that sound on DC locomotives with an armature bearing that is failing, but rather than jump to conclusions does anyone owning a Bachmann Williams 4-6-0 know what that sound is.  Again - forward direction only.

The tender doesn't stay attached either.  It unhooks and drags by the electrical connector.  I had to tape it.

Thanks,

John

NOTE:  Video was shot by using cardboard under the front and rear of the engine so only the center rollers touched the center rail with the drive wheels slightly above the outer rails so they could turn freely.  Tender was touching the track to complete the outer rail circuit.   I didn't have rollers to use so I rigged this up.  Thanks to Gunrunner John for the idea.

I attached a video with the noise.   Anyone?

Follow-Up:

Marios Trains was great.  Not only did they exchange the diesel for the correct one, they had their excellent repair tech repair the steamer making the noise in the video.  Apparently it was coming from the side rods.

I couldn't be happier with this forum sponsor.  It was my second order from them and won't be my last.

Thank you Mario.

John