"It's unbelievable. That they built so many trucks for the military," said Jim Bonds, 55, of Clear Spring, a plumber and pipefitter who has worked for Mack for 21 years.
Bonds got the history refresher courtesy of Mack Trucks' centennial celebration.
To mark the occasion, a 53-foot-long mobile museum of the company's history has begun crisscrossing the country, making its fifth stop at the Hagerstown plant off Pennsylvania Avenue.
"It represents our 100th year of building the world's most famous truck," said Roger W. Johnston, vice president and general manager of the Hagerstown plant.
The traveling museum is a kickoff to a yearlong celebration and provides a "sense of the important role Mack has played in the 20th century," Johnston said.
While the museum is open only to Mack employees and the media at this point, it will return to give the public a chance to tour Mack's history. A return date has not been scheduled.
The Mack Centennial Trailer Exhibit arrived Wednesday night so that the 1,425 employees at the Hagerstown powertrain plant could tour the museum. It is expected to head today to the company's plant in Winnsboro, S.C.
Mack Trucks has a rich history of helping out during wartime.
It was the "dogged" performance of more than 5,000 of Mack's AC model trucks on the battlefield during World War I that led British troops to nickname them "Bulldog Macks," according to the history display.
In February 1942, Mack suspended its civilian production so it could supply a variety of vehicles for World War II and allowed one of its plants to be used to manufacture the Vultee aircraft, according to the display.
The company's war time production earned the company the Army-Navy E Award.
During the Vietnam War, Mack supplied trucks used by U.S. troops in southeast Asia, according to the display.
The display also includes information about the company's involvement in the space program and the opening of the Hagerstown plant in 1960.
Reginald Keyes, 58, of Hagerstown, said the display had to mention the Hagerstown plant.
"Nothing goes without us," said Keyes, who works in engine assembly and will mark 35 years with the company in March.
The firm began in 1900 when the Mack brothers produced their first motorized vehicle, a bus, to provide sightseeing tours of Prospect Park in Brooklyn, N.Y., according to the display.
Guy Spitzer, 54, of Maugansville, said he was impressed with the way the museum covers the company's history from its beginning to its present.
The detail-oriented Spitzer even counted the number of birthday candles depicted on the side of the truck, noting the picture of the Bulldog blowing out the candles had the right number - 100.