Here is a photo comparison of both locos. The Lady on the right needs more jewelry. They are both HO scale. The Spectrum is on the left. I changed the headlight to match the Roundhouse. They both have the SoundTraxx Micro-Tsunami decoders.

Rich
Here is a photo comparison of both locos. The Lady on the right needs more jewelry. They are both HO scale. The Spectrum is on the left. I changed the headlight to match the Roundhouse. They both have the SoundTraxx Micro-Tsunami decoders.

Rich
While the Roundhouse is very plain as to details the availability of the 4-4-0, the 2-6-0 and the 2-8-0’s allows the modeler to acquire a roster with a strong family resemblance.
If Bachmann would only produce a Spectrum 2-6-0
Which ones which?? They almost look like 2 different scales.
Spectrum is the petite one.
Mark
The Spectrum is on the left. They are both HO Scale. I do not remember the history of their steam loco production but the Roundhouse might have been a little over size.
Rich
The Roundhouse comes close to the dimensions of one of the B&O classes of 4-4-0 before the TOC, M-60 of 1893. There were only 9 of them made so it matches something made in the real world.
Harold
MDC was one of the quintessential manufacturers of die-cast steam locomotives and very careful with their production techniques; I don’t think there is a scale problem but I do think that the MDC unit is representative of a huskier American Standard than that represented by the Bachmann.
Might the relative sizes of the two models in the photo above be distorted due to a wide angle lens?
The Bachmann Richmond 4-4-0 is a small 4-4-0 and the Roundhouse is just larger.

Harold
I use a close up lense on my Canon A70 for train photos. Here is a front view with driver diameters.

Rich
They actually aren’t all that different in overall size. However, the stack on the Roundhouse loco appears too large. IIRC, when the 2-8-0 kit came out in the 70’s, the reviewer said it scaled out at around 18 feet. My guess is the same situation exists with the 4-4-0.
Andre