|Horn and photo courtesy Brent Lee|
The PM-990 was
Prime Manufacturing's copy of the Leslie S-3K.
Externally, there are a few subtle differences between the Prime and Leslie horns, particularly
in the shape of the bell and power chamber where they meet the base. The Prime castings are
also somewhat heavier than Leslie castings, and the absence of the Leslie trademark on the
manifold is a dead giveaway.
Factory tuning is: D# minor (D#,F#,A#)
Prime no longer manufactures locomotive airhorns, but examples of the
PM-990 can still be heard on some former Burlington Northern locomotives. The sound is
essentially indistinguishable from an S-3K.
PM-990 sound samples:
Courtesy Dave Decker: