How The Term "Whistle Stop" Originated
Early in Truman's train-focused 1948 campaign, he experienced several embarrassing moments where he had not been adequately informed about the town he was addressing. Ken Hechler says in his book, Working with Truman: A Personal Memoir of the White House Years. New York: G.P. Putnam's, 1982. p.77.
"It was fortunate that these boo-boos happened early in the year, because every member of the staff could now appreciate the horrendous results of approaching a presidential speech without preparation or full communication with those responsible in the special counsel's office. The President gave specific assignments to each staff member, to head off any repetition of the blunders."
Balm for the President's injured feelings came that night at a big stadium in Butte, Montana, where he received a boisterous welcome. Once again he lambasted Congress, and he attacked Ohio's Senator Taft, who had urged people to fight inflation by eating less. "I guess he would let you starve, I don't know," the President said.
Stung by the criticism, Taft made a nationwide radio address to counterattack. On June 11, he made a speech at the Union League Club in Philadelphia, which accused Truman of "blackguarding Congress at every whistle station in the West." Truman and his staff loved it.
In Los Angeles, when the President blasted Congress again, he jokingly referred to the fact that Los Angeles was the biggest whistle stop he had visited. The crowd roared its approval. The Democratic National committee picked up the bait, and telegraphed thirty-five cities and towns along Truman's route to ask the mayors how they liked to be referred to as whistle stops---stations where you had to pull the cord on the train to make it stop.
It must have chagrined Senator Taft to learn that when he referred to a "whistle station," the President edited his phrase to read "whistle stop," and then the Truman phrase not only stuck in the public mind but also became one of the accepted political descriptions of the Truman style of campaigning.
Webster's THIRD NEW INTERNATIONAL DICTIONARY, p. 2606, includes definitions of "whistle stop" used as both a noun and a verb to connote the type of grass-roots campaign initiated by President Truman in 1948.