BIG MIKE & little mike...

That is a K-Line 2-8-2, with the Vanderbilt tender??  Is that the original K-Line provided

tender?  Nice looking. Is an On30 "scale" loco the same size as an On3?

That's a custom weathered Kline scale 2-8-2 I upgraded to EOB with a Lionel Vanderbilt tender. I'm starting to downsize and might put it up for sale in the near future.  I have several other similarly modified Lionel and MTH locomotives.

On3 and ON30 are the same scale; O. The difference is the gauge of the track; On30 is "30 inch" (or HO) and On3 is 36".  Lot's more stuff available in On30 since it runs on HO track and Bachmann has a lot of On30 equipment available.  The MMI locos need a fairly large radius curve vs. the Bachmann.

I am well aware of On30 vs. On3, and that there are all different sizes of, nominally, "O" gauge locomotives, scale and not so scale models of an NYC Hudson, etc., so just wondered if those liberties were taken here, and if the loco was the same size as a brass On3 version.  However, ignore that question....your K-Line Mike is nice looking.

The MMI locomotives are all 1:48 On3 or On30 - only difference is wheel spacing.  Don't know about other brands.  MMI was a division of PSC.

You're correct about "O" 3 rail manufacturers and gauge vs scale.. That's why I said "...O gauge scale..." in the original post referring to the Kline loco.

WBG Pete----  Is that a Lionel Vanderbilt tender from a Lionel UP Harriman 2-8-0?

Lionel SP Harriman 2-8-0 or a Lionel SP "Daylight" 4-4-2; I can't remember.  I modified both with EOB and coal tenders.

Excellent! There is a picture that I had seen somewhere that had a standard gauge loco (unknown config) next to a narrow gauge loco (similar unknown config) that exemplified almost the same perspective as your photo. Really neat to see that there is such a difference in size. Perhaps it was an advertisement in a publication for a video series or something if I recall. Either way, neat stuff!