The largest and strongest of those subsidiaries was the Florida Motor Transportation (FMT) Company, based in Miami, which had begun in 1919 – as a result of a merger between two other firms, each likewise based in Miami, and each of which had started in 1914 – the Clyde Passenger Express, running 32 miles (51 km) southward to Homestead, and the White Star Auto Line, running 60 miles (97 km) northward to West Palm Beach.
The second largest firm was the White Stage Line Company, which had begun in 1918 as the White Bus Line, running between Tampa and Saint Petersburg – eventually, starting in 1924, along US highway 92 (US-92) on the new Gandy Bridge across Tampa Bay, which shortened the distance from 43 miles (69 km) to 19 (30 km) – and which extended to Orlando in 1924 and to West Palm Beach in 1925.
The FML began operating that route in 1936, while the road was still under construction, at first relying in part on two ferry-boat rides which spanned two gaps among the islands until 1938, when the last bridge became complete and open for traffic.
By 1957 the Florida GL took part in major interlined through-routes (using pooled equipment in cooperation with other Greyhound companies) – that is, the use of through-coaches on through-routes running through the territories of two or more Greyhound regional operating companies – connecting Miami and Saint Petersburg with Los Angeles, Houston, New Orleans, Saint Louis, Chicago, Louisville, Nashville, Memphis, Birmingham, Atlanta, Detroit, Cleveland, Cincinnati, Toronto, Buffalo, Pittsburgh, Boston, New York City, and Washington.
In 1987 The Greyhound Corporation (the original Greyhound umbrella firm), which had become widely diversified far beyond transportation, sold its entire highway-coach operating business (its core bus business), to a new company, named as the Greyhound Lines, Inc., called also GLI, based in Dallas, Texas – a separate, independent, unrelated firm, which was the property of a group of private investors under the promotion of Fred Currey, a former executive of the Continental Trailways (later renamed as the Trailways, Inc., called also TWI, also based in Dallas), which was by far the largest member company in the National Trailways trade association.