16" Radius Helix For 14.5" - 16" - 17.5" Tracks (Best for N scale). Fully modular and up-gradable MDF helix system. It can be assembled and disassembled in less than 2 hours, which enables you to move or change your layout and modify your helix with ease. Very strong despite being modular.A dedicated spacer to adjust vertical distance between rings is included. Please see pictures for specifications and manual. Other Proses Tools & Kits You Might Be Interested. Proses Powered Railers For Z, N, HO, O Scales - YouTube. N Scale 16 Radius Helix For 14.5 16 17.5 Tracks" is in sale since Saturday, February 29, 2020. This item is in the category "Toys & Hobbies\Model Railroads & Trains\N Scale\Locomotives". The seller is "aaronyam" and is located in Istanbul. This item can be shipped worldwide.