The Westinghouse Air Brake Company (WABCo) is a name familiar to most railroaders. If the name isn't familiar, then their logo certainly is. Their logo, which appears to be a pair of 'X's with a line through the middle, appears on every part they produce. Wabco was never known for its air horns, though they did produce many varieties. However, they were, and still are, a major manufacturer of all sorts of railroad, nautical, and industrial products, including many different types of pneumonic systems like valves, vents, hoses, cylinders, and more. Now called Wabtec, they area also a major competitor in these markets overseas in places as far-reaching as Australia.
Wabco, as I will continue to call them (since their air horns are marketed by their "Wabco Locomotive Products" subsidiary), has been around for over one hundred years. They, was the first major manufacturer of railroad horns, with the earliest catalog I am aware of showing horns as early as 1910. Since then, they have continued to produce and refine their offerings of "Pneuphonic Horns", as well as act as a reseller for replacement parts for other manufacturer's horns, too. I have even seen WABCO product spec sheets for complete Nathan P1 and P12 horns. For reasons unknown to me, WABCO horns never took a large percentage of the railroad horn market, and today, any WABCO horn is quite uncommon to be seen on an operating locomotive.
A series
A-1 - The A-1 was possibly the first air horn produced by WABCO. It consists of a bell, which includes a built-in nozzle, which bolts onto a back cap, which also acts as the mount and air orifice. The back cap could be ordered with a lower mounting foot so the horn could be bolted onto a horizontal surface. Another, more rare back cap, was one that allowed mounting on a vertical plane. This back had two holes tapped to accept bolts that would attach the horn to the vertical plane from behind. The diaphragm of an A-1 is a single, thick disk with a weight riveted to the middle of the disk. This feature is present in all Wabco A-series horns, and as far as I can tell is also unique to A-series horns (with the exception of the B-6 - see below). A-1s generally have a straight, brass bell, but could also be ordered with a bell that curves outwards 90 degrees (see photo). The bell is similar in appearance to the much more common A-2, except that there are no "ribs" on the side of the bell.
Two different size bells were available for the A-1, the larger tuned to D#, and the smaller tuned to G.
On horns using the larger bell, a diaphragm with a larger weight was used.
Some early incarnations of the A series, which may or may not have been classified as an A-1, used slightly different bell styles or base styles.
One common difference among early models is whether through bolts are used to assemble the horn, or if not, if the bolts attach from the bell's or base's side.
The final incarnation of the A-1, though, uses a base virtually identical to the A-2 horn; the two may even be interchangeable.
AA-1 - The AA-1 is quite possibly the world's first railroad chime horn. It is nothing more than both A-1 bells bolted to a common back cap/mount. The mount for the AA-1 could also be ordered allowing the horn to attach to either a horizontal or vertical plane. It plays a major third interval, D# and G. Just like the A-1, the AA-1 could also be purchased with bells that are tilted 90 degrees; this application was common on many early MU cars.
A-2 - Of all the WABCO horns, the A-2 was probably the most common model.
A slight refinement on the A-1, this horn uses four support "ribs" on the side of the bell which give the bell much more rigidity towards the base.
It also had two possible bells, a longer 15" bell which sounds D and a shorter 11 5/32" bell which sounds G.
Like it's forerunner, the A-2 has two different diaphragms as well, one with a larger weight, and one with a smaller weight, used depending on which bell it will be used with.
However, the A-2 was not offered with a back cap that allowed attaching to a vertical plane; a mounting foot for use on a horizontal plane was the standard.
Construction for this horn was generally cast-iron, making it one of the more heavy horns, especially for its size!
The A-2 found its way onto many switch engines, most notably early ALCOs, and can still be heard on some engines today.
AA-2 - The AA-2, like the AA-1, is the two-chime combination of both available A-2 bells. It sounds a fourth interval - D and G. The AA-2 was a common horn on many interurban and MU cars, as well as on small industrial locomotives. There are still today many surviving on New Jersey Transit electric MU cars. Currently, the AA-2 is the only horn offered by Wabco.
A-6 - WABCO also produced an A-6 horn, which looks like a large A-2. It has the same support ribs on the side of the bell, and has a mount very similar to the A-2's mount. It even uses a weighted diaphragm. Two sizes of the A-6 were offered, though the long-bell A-6 is rare to come by. Unfortunately, I don't know for certain what notes the A-6s played, though I am told that they may have played A (long bell) and C (short bell). To my knowledge, an AA-6 was never cataloged or produced.
| aa1_landers_1.jpg | the back of this rare AA-1 shows the alternate, vertical-plane mount offered for Wabco's early horns (Copyright Lance Landers, used with permission) | |
| a1_conrad_1.jpg | here is a picture of a rare Westinghouse A-1 with the angled bell | |
| a1_waugh_1.jpg | William Waugh donated the next three pictures of this excellent A-1 | |
| a1_waugh_4.jpg | note the bell is brass, the diaphragm housing is bronze, and the base is cast iron | |
| a1_waugh_7.jpg | the base to the A-1 is identical to the A-2 base | |
| aa2_2001_2.jpg | here is my AA-2 with the diaphragms removed so it's easy to see the weights on each | |
| a6_031231_1.jpg | my A-6 shows that it's slightly different from an A-2, and uses a standard horn mount | |
| a2_warrick_1.wav | an A-2 in active service on a CF7 locomotive on the Blue Mountain and Reading (Copyright John Warrick, used with permission) | |
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| aa2_020518_1.wav | my AA-2 is blown, with a steam whistle following, at the 2002 Altoona blow |
B series
B-6 - Any horn in the WABCO B series is very rare to find. The B-6 in particular was offered only a short time, presumably just prior to the introduction of the B-7 and A-6 models. Like the A-6, I don't know the actual notes sounded, though they should be identical to their A-6 counterparts. I have also been told that the support ribs on a B-6 bell taper up as they meet the diaphragm housing, whereas the A-6 ribs are straight.
B-7 - The B-7 horn is actually very different from the B-6. This horn uses a single stainless diaphragm with no weight, and has an adjustable back cap. Also, the diaphragm housing and mounting foot are all one assembly, with the bell cast separate. The bells are screwed into the base, and locked with a pin that is hammered in place. There are four different sizes of B-7 horn bells, each playing a different note. The B-7-21 plays A below middle C, the B-7-25 plays middle C, the B-7-30 plays halfway between D and D#, and the B-7-36 plays halfway between F and F#. More often than not, the B-7 horns would be part of the E-2B horn combinations, though they do occasionally show up on their own.
| b7_longshore_1.jpg | Nick Longshore was kind to donate this photo of a B-7, most likely the B-7-25 |
D series
D-5 - The Wabco D series horns are a much smaller horn than the others offered. Like the A series, there were two bell sizes, long and short. The horns actually resemble a truck horn, and consist of the bell/base/diaphragm housing unit, and a back cap which bolts to the back of the diaphragm housing. The diaphragm is a single disk, and is identical whether you have a long bell or short bell D-5. What makes this horn somewhat unique is that there is a bolt that adjusts tension on a spring-loaded rubber disk which rests against the back of the diaphragm. By adjusting the screw, which locks in place with a lock nut, you can adjust the operating pressure of the horn. The D-5 was introduced around the same time period as the A-1, and hasn't changed much, if any, throughout it's life. The long bell D-5 plays F (?), and the short bell plays G#.
DD-5 - Just like the A-2, the D-5 was offered in a two-note configuration, the DD-5. The DD-5 from Wabco is unique in that the short horn is mounted vertically above the long horn. The notes played are F and G#, a minor third interval which sounds strikingly similar to the two-note car horns found on domestic cars in the last few decades. Wabco allowed others to produce the DD-5 as well. Bendix-Westinghouse is one name that appears on some of these horns. Some of these appear in the vertical configuration, and others appear in a more traditional horizontal orientation of the bells. Since the DD-5 is still produced today, and was introduced at the same time as the D-5 and A-1, it is the longest production air horn that I'm aware of, and is still in production today!
| d5_kanne_2.jpg | Ken Kanne's D-5 isn't very large, but has a big sound none-the-less | |
| d5_kanne_4.jpg | here you can see the markings on the back cap, as well as the allen key bolt used to adjust diaphragm tension | |
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| d5_kanne_1.wav | as I said before, it does have a good sound! | |
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| dd5_011225_1.wav | my DD-5 sounded prior to cleaning - now it sounds a minor third instead of this perfect 6th |
E series
E-2 - Competing with Leslie's Tyfon A-200 is Wabco's E-2 horn. This horn is the deep-note horn that WABCO offered, and was used on many early diesel locomotives. Though more mellow to the ear, this horn was not as popular as the Leslie A-200. I would assume this was due to marketing, since none of Wabco's products seemed to be as popular as alternatives offered by Leslie, and later AirChime and Nathan.
The horn itself was cast iron on early models, and sand-cast aluminum on later models.
Like Leslie's Tyfons, and Wabco's B series, it has a separate bell which was screwed into the diaphragm housing and secured with a lock pin.
It also uses a screw-on back cap to adjust tension on the diaphragm.
The diaphragm assembly, unlike a Tyfon or Wabco B series, is a complex unit consisting of 14 pieces!
The main diaphragm leaves are three disks thick, and the clapper consists of 6 disks.
The entire unit is bolted together with additional spacers and washers, and locks with a cotter pin.
On the aluminum models, the nozzle is not aluminum, but rather a stainless steel piece fitted into the diaphragm housing.
The E-2 blows an E below middle C.
The E-2 could be found on all sorts of power, from road engines to switchers, and some even found homes on steam locomotives! The last major order of E-2s that I'm aware of were for ATSF's CF7s, which were built in the mid-70's, I believe. However, up until sometime in the 1990s, Wabco still manufactured the E-2, though for export only in the end, giving it a production run of over 80 years! Today, the E-2 can still be heard on some shortlines and industrial locomotives.
E-24 - Not much is known about the E-24. I've never heard of it being used outside of the E-2B-2 three-chime horn. By itself, though, it would sound 248Hz, or B natural below middle C.
E-44 - The E-44 is also most common as part of a chime horn, the E-2B-3 in this case. However, there are reports of single-bell E-44s in service, though these are most likely from E-2B-3s which were disassembled. The E-44 looks like an E-2 with a really short bell. However, unlike the E-2, the bell is integral with the diaphragm housing and mounting foot. Also, the diaphragm on an E-44 is nothing more than a pair of stainless disks; there is no complex assembly, separate clapper disks, spacers, or bolts to hold it all together. The reason for this is that the E-44 is designed with the outer cushion ring in the same plane as the nozzle surface, similar Wabco's B series. The E-44 blows the note A, 440Hz.
| e2_2001_1.jpg | a photo of my first E-2 - I had just started cleaning the base of the bell | |
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| e2_020928_1.wav | my pair of E-2s blown in the evening at Brent Lee's Missouri blow in 2002 |
E-2B three-chime horns
E-2B-1 - In 1954, Wabco introduced three-chime horns with which they hoped to compete with Leslie and Airchime. These horns consisted of three different single-note horns mounted on a common plate/manifold, with the outer bells turned outward 5 degrees. Unfortunately, the horns were not very popular, and didn't see many applications. The E-2B-1 was by far the most popular of the three configurations offered. The first offering of the E-2B-1 used an E-2 horn with the short bell and long bell B-6 horns mounted along side. However, this was revised very early on, and most of the E-2B-1s that were produced use the newer configuration: it consists of an E-2 bell flanked by a B-7-21 and B-7-25. The horn, regardless of whether B-6 or B-7 bells is used, blows a low, steamboat-like chord - E A C.
E-2B-2 - This was the second horn offered in the E-2B line of three-chime horns. It consisted of an E-24 bell along with B-7-30 and B-7-36 bells. It would blow B, halfway between D and D#, and halfway between F and F#. However, I don't know if any of the E-2B-2s, or any E-24 bells, were ever produced. I've never heard of their application on a railroad locomotive, at least.
E-2B-3 - The final horn in the E-2B series is the E-2B-3. This horn was not as popular as the E-2B-1, but did see some railroad applications. It is constructed with an E-44 bell flanked by B-7-30 and B-7-36 bells. The notes this horn plays are halfway between D and D#, halfway between F and F#, and A. Because of the odd tuning of the B-7 bells, this horn sometimes sounded like it was playing a major chord, and other times sounded like it was just off and a little flat.
| kaspriske_030614_2.jpg | Ed's E-2B-1 next to an A-200-156 - note the back caps on the E and B horns, as well as the special three-horn base | |
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| e2b1_030614_2.wav | here is Ed's E-2B-1 while mounted on a GE at Oak Ridge 2003 | |
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| e2b1_030614_5.wav | it had just started raining when Ed's horn was mounted, but she sounded good anyway! | |
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| e2b3_020518_1.wav | someone is blowing Roger Granlund's E-2B-3 below Horseshoe Curve at the Altoona 2002 blow |
last updated 02.17.2004