If you don’t know the particular prime mover and proper air horn(s) for a specific locomotive, the task of choosing the correct dieselTsunami can seem confusing. Our new sound selection guide will point you in the right direction. While we can not tell you exactly which horn was used on a given locomotive on a particular day in history, we can help narrow your choices to those that were most commonly used by a particular road. Keep in mind that many of our prime movers are available in multiple decoder formats, i.e. TSU-1000, TSU-750, TSU-AT1000, TSU-BW1000,
TSU-GN1000 or TSU-KT1000. We hope you find this guide useful and fun!
The term prime mover refers to the diesel engine that is found in each locomotive. Tsunamis are available with each of the most common prime movers found on many diesel locomotives. Although different locomotive designs may have the same prime mover, they may produce slightly different sounds. These differences are due to how the prime mover is mounted and how the exhaust manifold is set up. To accommodate this, the Tsunami has a 7 band equalizer that can be adjusted to make each locomotive have it’s own unique timbre. Locomotives also differed in their gear ratio design. Some were designed with very low ratios for yard switching, while others had higher ratios for high-speed passenger train operations. The Tsunami allows you to set the top speed and adjust how fast it reaches its highest notch through a user adjustable speed curve and momentum CVs. Some locomotives contain two of the same prime mover. The EMD E8 for example has two 567 prime movers. To better accommodate this sound a modeler should consider adding a second speaker and boosting the equalizers low-end volume.
Below is a list of prime movers and the locomotives’ to which they correspond. Simply locate your locomotive on the prime mover chart below. For example, if you have a GP 40 you will find it listed under EMD 645 Turbo. Thus, the correct Tsunami would be an EMD 645 Turbo (2nd generation).
| Use the links below to see the chart for a prime mover and its corresponding models. | |||
EMD 567 |
ALCO 539 |
GE 'Cummins" Diesel | |
| ALCO 244 prime mover | ||||
|---|---|---|---|---|
| FA-1 | RS2 | PA-1 | RSD-4 | DL-814 |
| FA-2 | RS3 | RSD-5 | ||
| FB-2 | RSC-2 | RS4 | ||
| RS5 | RSD-7 | |||
| RS10 | RSC-3 | |||
Selecting the air horn
The most distinctive sound heard on a diesel locomotive is the airhorn. Railroads used airhorns to warn vehicles and pedestrians as well as to communicate to other trains, yard personnel, and trainmen. Listed below are a few examples of common signals used with air horns on many railroads.
| - - o - | Approaching a public road |
| - o | Warning for areas where view is obstructed |
| - | Approaching a station or flag stop |
| - - | Release brakes |
| o | Set brakes |
| - ooo | Flagman protect the rear of a train |
| ooo | Stopping (When in motion) |
| ooo | Going in reverse (When initially moving) |
| - - | Going forward (when initially moving) |
| oo | Acknowledgement of signal not otherwise specified |
One of the great features of sound decoders and DCC is the
ability to incorporate prototypical horn signals, just like the real thing! The
Tsunami has functions for both a long horn blast and a short horn toot making
crisp and accurate signals possible. Tsunami decoders also come with the
ability to set up automatic signals such as forward (--), reverse (ooo), a
public grade crossing (- - o -), and brakes applied (o).
To make your selection easier and more fun, each diesel Tsunami decoder comes with 16 different air horns that were most commonly heard for the era and prototype. Many railroads used more than one type of air horn. Since Tsunami offers so many different air horns in each decoder, you don’t have to permanently commit to any one. Remember this is your railroad - so don’t hesitate to select the horn you enjoy hearing the most. If you are interested in sticking closely to prototype practice you can read more information on which air horn is appropriate for a specific road by checking our document entitled Locomotive Air Horn History.