O N 30

O scale 30" narrow gauge

So if it's 1:48, (O scale) how is it that their smaller?

Because narrow gauge lines are smaller and cheaper to construct if the traffic and terrain don't allow a standard gauge railroad. Less material in construction.

Nice pix,but what scale are ON30 Eng. & cars?

The locomotives and rolling stock are, as indicated earlier, 1:48 scale.  They are correct for the significantly smaller prototypes (as seen in the photo where a narrow gauge locomotive is seen alongside a standard gauge locomotive), but they are nevertheless true 1:48 scale.  In On30, accessories used, such as buildings, figures, etc. would also be 1:48 scale.

Maybe this link would help? http://en.wikipedia.org/wiki/Narrow_gauge_railway

A friend told me that they are 1/48 not 1:48 (1 to 48) Which is O SCALE.

1/48 and 1:48 are just alternate ways of describing the same scale.

As others have said here, On30 is exactly the same scale as any other O scale models.

Jim

Jim is correct.  

Read 1/48 as a fraction, one forty eighth.  Everything is 1/48 the size of the prototype.

Read 1:48 as a ratio, one to forty eight.

ChipR

The SCALE is the same. Track Gauge is different. Both of these are O scale 1/48 or 1:48.

The little 4-4-0 is 1/48 scale running on a scale 30" track.

The 0-8-0 is 1/48 scale running on standard gauge track.

Your friend told you wrong.