Premier Track Help

So, I am working on a Premier LSM coaster, I would like to use the CK to make the spine thicker like on Full Throttle @ SFMM

Does anybody have an idea how I could figure out the dimensions of the spine and crossties? I've always struggled with modeling to the correct scale.

[Turbo]

my guess for the spine is a tube approximately 40 centimeters in diameter and the sides are about a centimeter in on each side, so about 38cm wide. as for the crossties I'd think they are boxes approximately 5cm x 5cm

EDIT: maybe 7x7 on the crossties