Maybe combined speed of both the trains speed. Maybe they both are running at 100 and the effect it is creating is being referred to as 200kmph crossing.
please wait...Translate to EnglishBruh, it's possible that both of them trains speedy as hell, hitting 100 each, and when they cross paths, it appears like they going at 200kmph.
please wait...Translate to HindiShayad dono trains ka speed milake dekho, ho sakta hai dono 100 ke speed se chala rahe ho aur uska asar hai ki vo 200kmph ki crossing kar rahe hai.