Selecting the Right Sound for your Diesel Locomotive

If you don’t know the particular prime mover and proper air horn(s) for a specific locomotive, the task of choosing the correct diesel Tsunami 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-GN1000 or TSU-KT1000. We hope you find this guide useful and fun!

Selecting the Prime Mover

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).

EMD 567 prime mover (1st generation, non turbo)
E-units F-Units ‘Geeps’ SDs Switchers
E3* FT GP7 SD7 NW2
E4* F3 GP9 SD9 SW1,6,7,8,9
E6* F7 GP15 SD24** SW1200
E7* FP7 GP18 BL1
E8* CF7 GP20** BL2
E9* F9 GP30** DD-35
GP35**


*E- unit locomotives were equipped with two prime movers
** The GP 20, GP 30, GP 35, and SD 24 are equipped with turbo charged versions of the EMD 567 and sound similar to the 645 turbo. We recommend using the EMD 645 turbo Tsunami for these locomotives for a more prototypical sound.


EMD 645 prime mover (2nd generation, turbo charged)
F-units ‘Geeps’ SDs Switchers
FP40 GP40 SD26 SD40-2 DD-40X
F40PH GP40-2 SD35 SD40T-2
FP45 GP40TC SDP40 SDL-39
F45 GP50 SD39 SDL45-2
GP-15T SD40 SD45X
SD45 SDP45
SD50


EMD 645 prime mover(2nd generation, non-turbo charged)
‘Geeps’ SDs Switchers
GP-15-1 SD-38 SW-1500
GP-28 SW-1504
GP-38 MP-15
GP-38-2 MP-15AC


*The GP38, SD35, and SD38 were equipped with a non-turbocharged version of the 645 prime mover and sound similar to the EMD 567. We recommend using the EMD 567 (1st generation) Tsunami with these locomotives.

EMD 710 prime mover (3rd generation, turbo charged)
F-units SDs “Geeps”
F59PH SD60 SD60F GP-60
F59PHI SD60M SD60MAC GP-60B
F69PH-AC SD70 SD70M
SD70MAC SD70ACE
SD90 SD90MAC
SD90M


ALCO 539 prime mover
HH-660 S-1
S-2
S-10^
S-11^

^The S-10, S-11 and RSC-13 were built by Montreal Locomotive Works; who took over production of ALCO locomotives and prime movers in 1970


ALCO 539-Turbo prime mover
DL-105 HH-900 RS-1 S-2
DL-107 HH-1000 RSD-1 S-4
DL-109 RSC-13^ S-12^
DL-110

^The S-12 was built by Montreal Locomotive Works; who took over production of ALCO locomotives and prime movers in 1970


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
RS10


ALCO 251 (V12)
FPA-4 RS-11 DH-643** RSD-12 C-420 M-420
FPB-4 RS-18*
RS-32
RS-36


*The RS –18 was built by Montreal Locomotive Works, who took over production of ALCO locomotives and prime movers in 1970.
**DH-643 is equipped with two of the 251 12 cylinder prime movers, we recommend adding a second speaker for a more realistic effect.



ALCO 251 (V16)
RS-27 RSD-15 C-424 M0630
RSD-17 C-425 M-636
C-430
C-630
C-636
C-855*
C-855B*


*C-855 and C-855B locomotives contain 2 of the 16-cylinder 251 prime movers. We recommend adding a second speaker for a more realistic effect.



GE FDL-16
U25B B30-7 Dash8-32BWH AC44CW C30-7
U25C B36-7 Dash8-40B C36-7
U28-B B36-8 Dash8-40BW C39-8
U28-C B39-8 Dash8-40BWH(Amtrakonly)
U28-CG B40-8WH Dash8-40C
U30-B Dash8-40CM
U30-C Dash8-40CW
U30-CG Dash8-41CW
U33B Dash8-44CW
U33C Dash9-44CW
U34CH
U36B
U36C
U50


Fairbanks-Morse
H-10-44 CFA-16-4 P12-42
H-12-44 CFB-16-4
H-12-44TS CFB-16-4
H-12-46 CFA-20-4
H-15-44 CFB-20-4
H-16-44 CPA-16-4
H-16-66 CPB-16-4
H-20-44 CPA-16-5
H-24-66 CPB-16-5
CPB-20-5
CPA-24-5


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.


- is designated as a long horn blast
o is designated as a short horn blast


- - o - Approaching a public road
o is designated as a short horn blast
- 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.