Tony Kaye has forwarded a September 1974 article by Henry Austin Clark Jr. on the Vanderbilt Cup Races describing many of the breakdowns and accidents."Generally we find one thing or another that goes awry when we attend a race in modern times, and it was the same way in the old days."
Here is the section on the 1904 race.
The 1904 course
Driver George Arents, Jr. and his mechanician Carl Mensel.
Paul Sartori driving Alfred Gwynne Vanderbilt's FIAT
Joe Tracy and the 1904 Royal Tourist.
Wilhelm Werner's Mercedes at the starting line with referee William K. Vanderbilt Jr.
George Heath winning the 1904 race in a Panhard.