Hancock was a name familiar to the railroads during the days of steam. They produced many steam appliances, one of which was the popular long-bell three-chime railroad whistle. When the railroads started dieselizing, Hancock, along with the other manufacturers of railroad-used goods, needed to adjust their offerings if they wanted to remain competitive. One way which Hancock did this was by modifying their whistles so they could be used on diesel locomotives.
The reasoning behind Hancock entering into the air whistle market for the railroads is fairly simple. Besides needing to change with the times, Hancock already had vast experience with whistles, and no experience with horns. Also, diesels were still new, and many at that time still carried single-note honkers. These horns are anything but elegant and ear-catching to the general public. Therefore, Hancock built the 4700 and H4700 air whistles in an effort to revive the sounds of steam and try to romanticize the newer diesel locomotives.
Production of these air whistles was from the late 1950s until the late 1960s. New Haven was a large user of these whistles, and every FL9 purchased by the New Haven came from the factory with a 4700 on the roof, and an H4700 on the rear as a backup warning device. Unfortunately, it was found that at high speeds, some of the whistles were not very easy to hear, though there are recordings of examples to the other extreme as well. It was not very long before the Class I railroads ended up replacing Hancock whistles with horns, namely for safety reasons, as audibility isn't as good as a horn, and isn't consistent between whistles, either. The primary reason for this is the lack of CFM to drive the whistle to its maximum potential output - a 1/2-inch pipe (common for most horns, and what the inlet is threaded for on a Hancock) just can't provide the necessary 300-400CFM to properly sound whistles of this size. There were, and still are, several shortlines which continued to use these whistles, though this may change soon with new minimum decibel requirements for locomotive horns.
Offerings and Construction
Hancock offered three different models of their 4700 air whistle. The most common was the regular 4700, which consisted of their whistle along with a large, rectangular bowl in the same plane as the languid plate. This bowl, or reflector, is used to direct the sound of the whistle towards the front of the locomotive. The second model is the 4700-2. This whistle is basically the same as the 4700 except that it has an electric heating element installed in the bowl to keep it from freezing. The final offering was the H4700. This whistle does not include the reflector bowl. Aside from this difference, it is basically identical to a 4700. Often the H4700 is referred to as the 4710, though there is little information to substantiate this model number.
Hancock's air whistles are all designed so that the bell of the whistle is horizontal when mounted on a standard horn mount. All the whistles are a single-bell chime, playing the notes E A C# (A major triad) when blown on air. However, over time, a some of the whistles got off key and produced some variants. One common chord was E A D.
The early whistles used cast iron bells, while later models used aluminum bells (by far more common). The reflectors seen on some whistles were also cast iron, along with the bell cap and bell cover. The rest of the large parts, such as the bowl and languid plate, were cast in bronze. In addition, the whistles with reflectors had a built-in strainer in the base of the bowl. The orifice opened into the bowl through a cylindrical mesh strainer made of a phosphor bronze material. Sometimes this strainer would get clogged and would need to be cleaned - about the only maintenance ever needed on these air whistles.
|epry44.jpg||East Penn Railways #44 had a Hancock H4700 mounted on one of its hoods|
|h4710_weart_1.jpg||this beautifully restored H4710 belongs to Ray Weart|
|h4710_020627_3.jpg||here is a photo of my H4710 after I finished restoring it|
|h4700_warrick_1.wav||ex-Pennsy doodlebug #4666 carried a 4700 on the front end for several years before being removed from service (Copyright John Warrick, used with permission)|
|h4700_weiler_1.wav||Norman Weiler captured this 4700 in use on an RS1 on the Tioga Central (Copyright Norman Weiler, used with permission)|
|h4710_030614_1.wav||these last two clips are of my restored H4700 while blown at the Oak Ridge 2003 honk|
|h4710_030614_3.wav||these whistles really make use of all the air they can get|
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