Dual Tone Train Horn Circuit – Description

A dual tone train horn simulator circuit can be made using two NE 555 timers connected in cascade. Here instead of using two NE 555 timers a single NE 556 timer is used which is nothing but cascading two 555’s in one package and each timers works independently. Switch S1 can be used to start the horn. The circuit is simple and low cost but works greatly.

Circuit Diagram & Parts List

Dual Tone Circuit
Dual Tone Train Horn Circuit Diagram


R1, R468K
R3, R533K
D1, D21N4007
K18 Ohms Speaker
S1Push Button Switch


  • The output from the dual tone train horn is more than enough to drive a small loudspeaker directly. All you need to do is connect the circuit to a 9V DC power supply or a battery.
  • Assemble the circuit on a good quality PCB or common board. Constructing a bread board prototype is recommended.

This circuit can be modified to make the train horn turn ON when the train is about to reach different stations, level crossings, single lane tracks and so on. In the circuit above, a Switch (S1) is used to manually and momentarily turn on the two-tone horn. This horn can be turned ON automatically at certain points on the track by mounting a reed switches under the track at the point where the horn is to be heard. The reed switch will turn ON if the magnet is placed on the bottom of the train and it passes through the track. All you have to do is place the reed switch in such a way that it faces upwards.

We have more Tone Generator circuits in our website that you may like to read;

1. Doorbell Circuit

2. Multi Tone Alarm Circuit

3. Scream Generator Circuit

4. Musical Horn Circuit

5. Water Activated Musical Bell



  1. James Kamsoo

    I am looking for a Dual Tone Timer that is used on Longline Fishing Vessels for the Hooks and Buoys. Ideally we would like to output 12Vdc to activate a Pizeo Siren. Plus have the first tone triggered every 4 seconds (preferably adjustable from 2 – 10 Seconds), After 4 Beeps on the first tone a second tone is sounded but of a different sound level. Ideally the first Tone is to hook the hooks onto the line and the second tone is for the Buoy to be hooked on to the line. Willing to elaborate more if i am not understandable. Thanks and hope we can work together on this.

  2. I built this circuit but get more of a convenience store door alarm out. Dosn’t sound like a train at all. The only difference is I used two 555 timers and they are not the same. One is a 7555 and the other is a 1455. Could this be my problem?

  3. sir can you tell me how to make tones of bird???