What is The worlds most lagest Company?

This depends on what parameters you choose. Are you asking about number employees? Gross revenue, net revenue, area of coverage, etc? You'll need to be more specific.

Whilst Indian Railways have the largest number of employees, The Soviet Rail system has the largest distance of trackage. Coca Cola has the largest fleet of vehicles, there's a toss between United Airlines and American over who is the largest.....is it by number of aircraft, including the ones rotting in the desert? Or is it by number of passengers flown, or is it by distances such as British Airways and Qantas? Is it by service such as Singapore Airlines or Emirates