I'm working on a project to equip model locomotives with sound boards. I'm in the process of designing the board at the moment, and the idea is to allow users to load their own sound files onto an SD card plugged into the board.

Conventionally, model locomotive sounds are collected from high-fidelity microphones placed on and around the real engine in question. The engine is started up then put through idle and all of the different notches, as well as dynamic braking, horn and bell sounds, etc. This practice is very expensive because you have to find a willing (usually small) railroad or museum, pay for travel expenses, and diesel fuel ain't exactly cheap at the volumes these engines go through. Secondly, newer engines are hard to record because railroads aren't exactly in the business of letting hobbyists tape microphones all over their money making machines. As such, the main cost for a sound board comes not from the circuit's BOM cost, but from the effort required to get sounds from locomotives.

What there's plenty of are YouTube videos of amateur rail enthusiasts taking videos of locomotive sightings at close(ish) proximity, including startups and shutdowns. My question is - is there a way to take a bunch of different audio recordings of the same engine, remove noise and the doppler effect, and from that create a profile that can be used to simulate what the engine might sound like at different throttle notches?

For this exercise let's overlook the licensing and copyright side of things. I'm more interested in learning if there's a way to do this.

Some sample clips (all different engines):

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    Food for thought: There are sound recordings available done by skilled enthusiasts and professionals . I am a train fan and model railroad lover and if i where to have your product i would want it to be authentic. I.E. If i had an Engine of fame and reputation i would want the recording that it played to be a recording of that specific Engine, not another engine and surely not a simulation. Authenticity is of paramount importance to model railroaders. duckduckgo.com/…
    – Alaska Man
    Dec 11, 2020 at 18:12
  • As you pointed out, these recordings are generally expensive to make. If there were a cheaper, quicker alternative then everyone would be using the cheaper, quicker method already. As Todd points out in his answer, it would take a lot of skill and time to reproduce what you want from a single recording - more than it's worth. Jan 6, 2022 at 21:42

1 Answer 1


Sort of yes, but if you can buy professionally made samples that’s probably much easier and might even be less expensive.

Removing noise can be done with different degrees of effectiveness depending on the original audio and the de-noising tool(s) used. Effective noise reducing software is often expensive because of market forces as well as competition to innovate and build in machine learning, etc.

Removing Doppler - well I expect it can be done but the only way I can think to do it is to automate pitch shifting to carefully cancel it out. This would probably be a long tedious process just for one sample and the results might be strange sounding. You might need a quality plugin or DAW with built in pitch adjustment and again that means money.

So if you want to spend $500 - $1000 on software and I don’t even know how many hours finding, isolating, and cleaning up the audio to get ok sounding samples at best, yeah maybe it could be done.

PS: About 35 years ago we had an HO layout. Back then I thought the smoke generating systems were the pinnacle of realism. I never really thought about what the digital age could bring to model railroading before now.

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