Can someone help me with the recommended track center clearance for HOn3 tangent (straight) track?
Unfortunately, it really depends on the equipment you are running. Things like the Roundhouse Shay - which is just a re-gauged version of their HO Shay - are wider than a lot of people think. Similarly, standard gauge cars put on HOn3 trucks will be excessively wide.
The HOn3 NMRA gauge was set up with older narrow gauge equipment in mind - the clearances don’t always work for models of newer equipment. K Class locomotives, passenger cars, and some of the specialty cars are examples.
In real life, land was cheap and available where there were multiple tracks. So close spacing of the tracks was usually NOT the prototype practice. Study photos for examples of this. The later a 3ft gauge railroad was built, the greater the clearances.
I like to use the 2" spacing of standard gauge for my HOn3 in most situations. This imitates the spread out look of the prototype. The exception is where there is a loading platform. Then I measure the cars I will likely use at that location to get the spacing of the loading platform and build accordingly. I will likely have other cars that can’t get by, just like in real life.
hope this helps
Fred W
Seems like within the last 100 years most NG lines had SG clearances. Whether it was because they might SG in the future, or they ran SG equipment with NG trucks over the line like D&RGW and EBT.
The rationales I remember reading for building ‘narrow gauge’ in the 19th Century had more to do with economizing on right-of way improvement costs (subgrade/drainage and grade, tie size, rail weight) and not with the ‘air rights’ of loading gage or lineside clearance.