What other methods could be used to ensure parallel rails (any method, not just the geometry kinds)?

use of  Wires , Clamps , and measuring tools

Step-by-step explanation:

To ensure parallel rails we can use : Wires , Clamps , and measuring tools as well

The use of wires are very effective and most stressful and they are used mostly when working with wooden rails  , while you can use Clamps and other measuring tools for every kind of rails to ensure they are parallel.

step-by-step explanation:

mean or average is 40.6