F-units, air horns                                                           TT00039




05/21/2001  8:20PM

Bill Kuebler

All NP F-3s, 5s, and 7s (freight and passenger) originally had Leslie  single-note horns, one facing forward and the other facing rearward. All NP  F-9s (freight and passenger), except 7050A, were delivered with Nathan  3-chime and kept them throughout their NP service lives. NP 7050A was an  ex-EMD demo unit, and it came with Leslie single note horns. This unit was  converted to passenger service in 1967 and renumbered 6707A; it got a Nathan  3-chime at that time.    The Leslie horns on all passenger F-3s, 5s, and 7s were gradually replaced  with Nathan 3-chimes during the period 1956-1963. Those years are real close,  if not exact, as end points of this time span. No passenger unit retained its  Leslies throughout its NP service life--well, except 6500C (1st), which had a  real short service life because it was wrecked (and destroyed) in August  1955. There was a 6500C after that accident (until 1965), but that one was an  F-9 with a Nathan 3-chime. It was renumbered 6703C in 1965.    The Leslie horns on most (slightly more than half) freight F-3s, 5s, and 7s  were gradually replaced with Nathan 3-chimes during the same period  (1956-1963). The freight Fs that weren't changed retained their Leslies  throughout their NP service lives. There is no discernible pattern as to  which of these units were changed to Nathans and which ones weren't. In the  freight F-3, 5, 7 groups, age of unit and model is not much of a determining  factor. There were several F-3s that got Nathans and some newer F-7s that  never got Nathans, for example. It would be a matter of looking at lots of  pictures and nailing it all down that way. I know of no written document in  the NP archives that details this issue.    Most of this horn replacement work on both freight and passenger units was  done along with lots of other appliance work on these engines--some of it  internal, such as brake equipment modifications to passenger units.  Authorization for Expenditure (AFE) files are not detailed enough to identify  specific units for the purpose here.    These answers are based on extensive photo analyses, personal recollections,  and familiarity with NP's AFE files.    For what it's worth...    The sound of a Nathan P-3 (3-chime) as compared with the Leslie horns should  be more than enough to convince you to go with the Nathan. As far as diesel  unit horns go, the Nathan P-3 sounds as beautiful as a diesel's air horn can  sound and has all the others you listed beat by a wide margin; the Leslie  BLAT horn sounds like a sick and angry cow, by comparison. But I'd take a  Leslie horn any day over one of those whatever-it-was horns on the CB&Q  E-units, at least the ones I heard in the 1960s and 70s. Those were the WORST  sounding horns I ever heard in my life. Whoever designed them was more than  unmusical; that person was diabolical and demented. It should have been  called the Frankenstein horn.  F3, F7, F9, air horns, Leslie, Nathan, 1950s  Compiler  C Frissell