Sn30 model railroads, 30 inch gauge railroads, were famous for industrial commodities hauling, mostly operated locally with some passenger service offered. There are many different one of a kind car types which makes modeling the 30 inch gauge layouts unique. Go to Big Indoor Trains, this site has a lot of info on 30" gauge railroads, it's a real good read! Sn30 equates to Sn2.5, as an "either or" expression of types

Modeling the (narrow track version) Sn30 utilizes certain Hon3 locomotives/rolling stock modifiable to compliment Sn30s 1/64th scale. Sn30's (narrow track version) track is the TT type, gauge .471 or 12mm. TT track is approximately 1/2% too narrow to be correct for a 1/64 modeling scale of a 30" narrow gauge railroad. The correct gauge is .469 or 11.9mm. TT track being so close in gauge and readily available is the accepted standard when modeling to the (narrow track version) of Sn30. TT track is available in rail codes of .040, .055, .070 and .083.