Ensuring the two rails remain equally distant from each other along the entire length of the runway.
First, a crucial clarification: . There is no widely recognized ISO standard numbered precisely "124881" (with a trailing "1" without a hyphen). The International Organization for Standardization (ISO) typically uses the format ISO XXXX-Y:Year . The most probable standard you are seeking is ISO 12488-1:2012 – Cranes – Tolerances for wheels and travel rails – Part 1: General principles . iso 124881 pdf
