Leslie S-3L

S-3L is a shorthand designation for any Leslie 3-chime Supertyfon horn that uses the #25, 31, and 44 bells (the "L" chord). The actual model designation of a given horn will have additional prefixes and suffixes as follows.

R=improved horn bells with spiked back caps
L=low profile manifold
U=very low profile "universal" manifold.

O=normal arrangement of bells from left to right is switched
F=full openings in orifice dowel pins (0.125 inch)
J=very narrow, tall manifold
R=one or more bells reversed (turned backward)

The designations can get quite complicated, and for the sake of simplicity, any S-3L with reversed bells is generally referred to as an S-3L-R. The horn pictured is an S-3L-RO, with the #25 bell on the left and the #31 on the right (standard arrangement is the other way around) and the #44 bell reversed. Other variations of the S-3L are shown below; click the thumbnail for a larger image:

The very earliest S-3L's produced in the early 50's featured bronze power chambers and two-piece bells. The mounting tabs around the periphery of the power chambers disappeared from the design about 1970. Horn and photo courtesy Brent Lee.
An RS-3L-RO. The R prefix indicates the use of the redesigned, spiked back caps (the "RS" modifications) which were introduced around 1980 in an attempt to reduce the horn's susceptibility to fouling. Inside, a stiffer, one-piece diaphragm replaced the earlier two-piece diaphragm, which resulted in a somewhat harsher sound.
An SL-3L-R. The L prefix indicates the use of the low profile manifold, which is shaped like a triangle. This horn also has the older style domed back caps, and is mounted on an extension so that the sound from the reversed #44 bell isn't blocked by the air conditioner box behind it.
A pair of modified RSU-3L-LR horns. Taking the designation one letter at a time:

  • R indicates the improved design with spiked back caps,
  • S indicates a Supertyfon horn,
  • U indicates the use of the oddly shaped, very low profile manifold,
  • 3 indicates a three-chime horn,
  • L indicates the L-chord,
  • L indicates the horn is to be mounted on the left side of the cab,
  • R indicates that one or more bells are reversed (the #44 in this case)

The standard arrangement of the horn bells on the very low profile base was #44, 31, 25 from left to right facing the front of the horn, but these horns have the bells arranged as #25, 44, 31. The U-base was for use in situations where the horn had to be mounted on the sloping part of the cab roof for clearance reasons. It was clearly not necessary for the locomotives pictured above, as the horns are not only mounted at the highest point on the cab roof, but are on extensions to boot!

Leslie also made two chime and one chime horn manifolds, and if desired, a multichime horn could be spread over several manifolds. The Santa Fe GP30 pictured above has the equivalent of an S-3L, with the #31 and 44 bells on a two chime manifold on the engineer's side, and the #25 bell on a single manifold on the fireman's side.
"Standard arrangements" notwithstanding, railroad horn shops can arrange the S-3L's horn bells any which way they choose. On this rearranged RS-3L-R, the #25 and 44 bells have switched places, and the #31 bell is reversed rather than the #44.

The S-3L was introduced in the early 1950's as competition for the Nathan M-3. It rapidly became one of the most popular 3-chime airhorns ever produced. The S-3L was used extensively by Santa Fe, Union Pacific, Milwaukee Road, Soo Line, Missouri-Kansas-Texas (MKT), Chicago & Northwestern, Kansas City Southern, Erie Lackawanna, Reading, and many others.

Prime Manufacturing Corp. of Oak Creek, WI produced a horn identical to the S-3L, which they called the PM-920.

Factory tuning is: 255, 311, and 440 Hz (approximately C, D#, A)

The S-3L was one of the most common multichime airhorns used by US railroads. In recent years, most of the large roads that used the S-3L have turned to Nathan horns instead. The horn remains in decreasing numbers on BNSF and former Conrail locomotives, as well as on regionals and shortlines nationwide.

S-3L sound samples:

Brent Lee's early S-3L (pictured above):
Sample 1...555kB...25 seconds

Santa Fe, various locomotives:
Sample 1...268kB...12 seconds
Sample 2...156kB...7 seconds
Sample 3...144kB...6 seconds
Sample 4...479kB...22 seconds
Sample 5...458kB...21 seconds
Sample 6...533kB...24 seconds

Conrail, various locomotives:
Sample 1...310kB...14 seconds
Sample 2...878kB...40 seconds

Union Pacific, various locomotives:
Sample 1...167kB...7 seconds
Sample 2...373kB...17 seconds

When bad things happen to good horns:

Early Supertyfons tended to get fouled easily by dirty/oily supply air or from foreign matter entering the horn. This caused bells to go silent or harmonically overblow (squeal). The RS modifications mentioned above helped to an extent, but squealing Leslies can still be found, particularly when the horns have the largest available orifices. With the advent of the North American safety cab and its button-actuated solenoid horn valve, the horn is instantly subjected to the full force of the air blast, resulting in greater wear and a tendency for bells to sound poorly or quit sounding altogether. Below are a few examples of S-3L's in various states of deterioration.

Horns with one bell not sounding:
Sample 1...264kB...12 seconds
Sample 2...490kB...22 seconds
Sample 3...211kB...9 seconds
Sample 4...550kB...25 seconds
Sample 5...189kB...8 seconds
Sample 6...275kB...12 seconds

Horns with two bells not sounding:
Sample 1...73kB...3 seconds
Sample 2...345kB...15 seconds
Sample 3...211kB...9 seconds
Sample 4...470kB...21 seconds

Horns with squealing bells:
Sample 1...123kB...5 seconds
Sample 2...980kB...45 seconds

Horns with squealing bells and other problems:
Sample 3...231kB...10 seconds
Sample 4...218kB...10 seconds
Sample 5...375kB...17 seconds

Horn in just a world of trouble:
Sample 1...288kB...13 seconds

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