As with the A-75 and A-125, Leslie's nomenclature for its A-200 Tyfon horns was complex and varied over time. The horn shown above and at left was known early on as the A-200-L, indicating that it was designed to be blown on air, had a 200mm diameter diaphragm, and had the "low pitch" bell that measured 24 and 29/32nd inches in length. There would also be additional letters on the end of the designation indicating the materials from which the diaphragm and the horn itself were made.
In later years, the horn was redesignated the A-200-156, with the final number giving the horn's fundamental frequency in hertz. As before, a pair of letters following the last number indicated the diaphragm material (M for metal, P for plastic, or R for rubber faced) and the metal used to cast the horn (A for aluminum, B for bronze).
Far less common in railroad usage was the higher-pitched A-200-H, whose bell measured 18 and 11/32nd inches. Later known as the A-200-233, it appeared on some early Burlington streamliners and possibly other early diesels. Photo courtesy Brent Lee.
Factory tuning for the A-200-156 was: D#
The A-200-156 was one of the most popular horns of early dieselization, showing up on thousands of EMD passenger and freight locomotives, as well as Pennsylvania Railroad's GG1 electrics, and even some late steam locomotives such as Southern Pacific's famous semi-streamlined Daylight 4-8-4's such as #4449. Single chime "honkers" fell out of favor with the advent of the multi-chime airhorn and are rare to find today. The A-200-156 can still occasionally be heard on older shortline locomotives and on museum engines.
A-200-156 sound samples:Sample 1...151kB...6 seconds
Sample 2...108kB...5 seconds
Sample 3...184kB...8 seconds
Western Pacific F-units, courtesy Dan Furtado:
Sample 4...1075kB...24 seconds