Nathan/Airchime P5 series - P5, P5a, P01235, P01345

Characteristics

Tuning

P12345 (P5): A major dominant 7th (C#, E, G, A, C#), with P-series bells #1, #2, #3, #4, #5
P01235: A major dominant 7th (A, C#, E, G, C#), with P-series bells 0, #1, #2, #3, #5
P01345: A major dominant 7th (A, C#, G, A, C#), with P-series bells 0, #1, #3, #4, #5
P1234a5 (P5a): C# diminished (C#, E, G, A#, C#), with P-series bells #1, #2, #3, #4a, #5

Sound

All P-series horns have a very brassy sound quite unlike any other horn. There is often a "chiff" sound just as the horn is blown.

The chord of a P-series horn is quite variable depending on its vintage. Older horns, if in proper working order, will sound the proper chord. However, new castings were made for the bells in the late 1970's which didn't respect the original specifications, with the result that bells #1 to #4 were generally one semitone too high and #5 one semitone too low. These horns are often referred to as "new-castings" P-series horns. The new castings sometimes result in a chord with D, F, G#, A#, C (such as SLR GP11 8749) which, although not the intended chord, is still quite pleasing. Much of the time, however, the horns simply produce a discord, such as with the two SLR GP40M-3 samples.

There were a few other tuning variations, but they were rare and are not often heard today. The P01235 had the #4 bell replaced by the 0 bell, which was an octave lower, while the P01345 had the 0 in place of the #2 bell. The P5a (short for P1234a5) had the #4 bell tuned to A# to produce a diminished sound in place of the A major dominant seventh. P5a's were used on the first order of Amtrak F40PH's; later ones had Nathan K5LAs.

Samples

• SLR GP11 #8749 (2001-02) - P135R24 (horn repaired)
• SLR GP40M-3 #3805 (2004-05-09) - P135R24 (discord)
• SLR GP40M-3 #3806 (2004-03-19) - P135R24 (discord)

• SLR GP11 #8749 (2000-06) - P135R24 (bells #1, #2, #3, #4 silent)

Appearance

Standard five-chime P-series horns can be told by their long and narrow shape similar to the K-series. The manifold is a V-shape, with two bells on each tip of the V and one in the middle. Power chambers are equal sizes on all the bells. On horns with the low-profile manifold, the back caps of the bells do not line up as they do on the standard manifold.

Classification and Use

Classification

The P-series follows a classification scheme slightly different than other Nathan/Airchime horns. The designations feature the numbers of all the bells, so the full name of standard 5-chime P-series horns would be P12345. This is often shortened to "P5". "R" is added to designate reversed bells, so a P5 with bells #2 and #4 reversed would be a "P135R24".

History

The P-series horn was initially introduced in the 1950's as a more reliable alternative to the maintenance-intensive M-series, and produced the same chord but with a much different character. It was soon followed by the K-series, a more refined horn that has proven more popular.

Locations

Standard P5's are found mainly on older Norfolk Southern and Illinois Central locomotives, but have been supplanted by K-series horns. Norfolk Southern often used pairs of P5's, one on each end of its locomotives, that were mounted on a lower-profile manifold. The P5a was used on the first order of Amtrak F40PH's and on Metra locomotives and also used the low-profile manifold. The P01235 and P01345 variations are rare.