Rail's Departure From Cites Was Hardly Voluntary, Market-Driven

General Motors, Firestone and Standard Oil used shell companies to buy up and discontinue street car lines so that GM, Firestone and Standard Oil could sell and keep buses running instead.

One account, here.

There's a dispute about whether the business combine legally-conspired to eliminate trolley systems but their front companies did buy and shut down trolley systems across the country, with bus systems replacing them.