Tunnel for N Scale Train Model Trains 18 degree variations mean that

18 degree variations mean that 5 of them make a 90 degree turn

and you can lightly sand the surface

For example

The curved variations list the degrees of a circle they cover

Tunnel for N Scale Train Model Trains 18 degree variations mean thatA simple 3D printed plastic tunnel for an N scale train track. Variations: Straight variations are straight, and their length is the listed number. The curved variations list the degrees of a circle they cover, and the radius is the radius of the curved track. For example, '15" radius, 30 degrees' means that each piece covers 30 degrees of a circle, meaning that 3 of them make a 90 degree turn. The radius of the circle that would be made by these