Sorry for the stupid question but I have found a nice coal layout but it is in “HO” scale, can I literally shrink the size by half and use it for “N”?
Short answer: Yes!
Longer answer: Not exactly half. HO is 1:87.1 and N is 1:160… so 87.1/160 is not exactly 1/2, but close 
What he said but…watch those aisle widths shrink down from a comfortable 36" to a deathgrip 18" opening.
OK, great…thanks for the advice
Of course the other option, if you have the space, is to build it in N using the exact same dimensions. Making allowances for passing tracks, sidings, roads, and overpasses of course. That approach might well turn a “nice” HO scale layout into a stunning N scale layout.
I did that exact approach with a salvaged Oregon Pass lines, I aquired. It was difficult to cut down the benchwork’s height at each point to achieve a lower grade but the 22" radius was far better in N Scale than it was in HO.
Cheers
Great idea, that would be cool
thanks
That was my thought too. For example a 4x8 HO layout using tight 18" radius curves is going to limited as to what equipment it can run - but 18" curves are considered “broad” in N scale and you could run bigger equipment, like 80’ passenger cars and huge steam engines or diesels…and of course, each train could be almost twice as long!
I’ve seen a lot of 4x8 plans that made me think that they would look really good if stretched out to room size. This would be a good oportunity to do so. Like the man said" be careful not to shrink your aisle size", and reduce siding spacing and yard tracks accordingly. BILL
N Scale = 55% of HO Scale
Step 1: N Scale = 1:160
Step 2: HO Scale = 1:87
Step 3: 87/160 = .54375
That being said, the width of a walk-in aisle is the same size for all scales because our hips are 100% Scale!
The Idea of using the “HO” space has much to recommend it. If you don’t have enough space Making the “N” 3/4 the size of the “HO” may be a good compromise.