Horn and photo courtesy Harvey Henkelmann. The photo depicts the all-bells-forward arrangement. The horn is sometimes used with one bell reversed.
The K3HL was introduced in 2010 and generally resembles the K3HA but with the long 1L bell instead of the 4a. Union Pacific has used the horn to replace the K3HA on locomotives where the latter doesn't comply with current decibel requirements.
Factory tuning is: C,D#,F# (261, 311, 370 Hz) The K3HL uses K-bells 1L, 1, and 2.
K3HL sound samples:
Sample 1...331kB...20 seconds
Sample 2...80kB...5 seconds
(Sample 1 courtesy Ron Chamberlain)