The conspiracy and they were convicted in court of criminal conspiracy which means it is legally speaking a fact rather than a story was between General Motors Standard Oil of California now known as ChevronTexaco Firestone Tire now owned by Bridgestone of Japan and Phillips Petroleum now ConocoPhillips They conspired to buy up and shut down  streetcar systems in  cities including the aforementioned Pacific Electric Railway system in LA which was the largest interurban electric railway in the world They replaced all the electric trains with GM buses running on Firestone tires burning Chevron and Phillips diesel fuel Of course the electric railways didnt make a profit back then but neither do the buses and freeways that replaced them except for the aforementioned companies of course