Non-hobbiest sellers often do not know what "scale" their model railroad items are and place them in the wrong ebay category.  In addition, many model railroad equipment manufacturers produce identical models in more than one scale.  Therefore, it is often very difficult to tell the scale of a model from just a photograph.  N scale and HO scale are very often confused for these reasons.  As a result, many buyers have received HO models when they were expecting N scale models.  (And vise-versa.)

To prevent such confusion and the resulting problems with item returns for buyers and sellers, I have written a brief explanation of the differences between these two model railroad scales and how a novice may tell them apart.

First, sellers whould always place an easy to read inch ruler near the model in its photograph.  That way, buyers will have a scale reference when viewing the photo.  This simple suggestion can eliminate unnecessary emails from buyers asking, "How big is it?" or "Are you sure it's that scale?"

About "scale": N scale is the second most popular model railroad scale in current use.  Its ratio is 1:160 -- or one actual foor (12 inches) equals 160 N scale feet.  Using a conventional inch ruler, an N scale foot would be about 1/16 of an inch long.

Example: a "forty foot" long boxcar model would be about three inches long in N scale.

Example: a "two story" house model would be about two inches tall in N scale.

HO scale is the most popular model railroad scale in current use.  Its ratio is 1:87 -- or one actual foor (12 inches) equals 87 HO scale feet.  Using a conventional inch  ruler, an HO scale foot would be about 1/8 of an inch long.

Example: a "forty foot" long boxcar model would be about 5-1/2 inches long in HO scale.

Example: a "two story" house model would be about 3-1/2 inches tall in HO scale.

Most N and HO scale locomotives and rolling stock can be told apart by their wheel gauge -- or the distance between the backs of their wheels.  In N scale, this distance is approximately 7/32 of an inch.  In HO scale, this distance is approximately 9/16 of an inch.

The scale of N and HO structures can sometimes be more difficult to determine as they come in all sizes and have various heights of door and window openings.  However, a standard "sever foot" tall "people" size exterior door in N scale will be about 1/2 an inch tall and in HO scale it will be about 1 inch tall.

The scale of N and HO figures (people) is easier to determine.  An average "six foot" tall standing N scale figure will be about 7/16 of an inch tall (not including a base.)  An average "six foot" tall standing HO scale figure will be about 13/16 of an inch tall (not including a base).

I hope this clears up a few of the mysteries of scale model railroading -- at least for N and HO scales.  (There are several other model railroad scales in use out there -- S, O, G, Z, TT, #1, tinplate, narrow gauges, etc.  But that will be for someone else to write about.)

Tom Levy