Thank you for your input. Excellent information!

Here's another type of "notching".

https://www.youtube.com/watch?v=T0R_28XbieY&ab_channel=TCRail

In the following, you can hear two distinctive sounds:

https://youtu.be/awclpPOWLbw?t=186

Here is a Amtrak AEM-7 with many sounds and a lot of lights too.

https://www.youtube.com/watch?v=Q-VpYfo6saI

Something like that with WiFi would perhaps be a strong advantage over the competitors' possibilities.

Nässjö Järnvägsmuseum, Da loket provköres juni 2016,

https://www.youtube.com/watch?v=w4aZk9dII2E

Newer locomotives or trainsets, continuously varying slider and electronic power control.

Some of them emitting a "frequency converter sound", some others are very quiet in the drive unit.

SJ Snabbtag dubbeltag mot Malmo avgar fran Stockholm (X2000),

https://www.youtube.com/watch?v=Fk-5UoWKEwQ

From the outside there is clearly a different sound comming from them. But normaly I think nearly every sound is masked by the masive cooling fans. Occasionally there is compressor and brake sounds to be heard. From the drivers cabin you can clearly hear the difference between old/new locomotives. Outside, you have to be very close to the locomotive to hear contactors or humming power electronics, I think.

Some older DC resistor locomotives, like in this example. the South African 6E1, the blower starts/stops depending on the throttle setting or/and the heat build up in the shunting resistors. This would be simple to emulate with a long sample that isn't changing pitch and gets looped. If it's long enough, it's hard to tell it's just looping over and over.

Last of the South African class 6E1's Part Three,

https://www.youtube.com/watch?v=RSOvZsFkmxY

Every locomotive is unique, so it's best to try to get/make soundfiles for "your" locomotive. All depends on how far to take it. Any generic soundfile is good enough. But some users might want to do it very realistic as far as possible. With LocoFi we can do whatever we want with the sound, for free, no costly programmer or messy user software which may take days to learn. Just a wav file, slide in the SD-card and off we go!

I think just the basic behaviour of what we want from the sound file is needed in the firmware/APP. Like for the running sound, constant pitch, speed following pitch. Loop or no loop for additional sounds, like bell needs looping, a coupler sound or compressor needs no loop. Start up and shut down time adjusted to the sound lenght.

Waiting for my X2000 train to arrive, my first electric canidate for being LocoFied.

This is what we know or have observed:

1. Throttle isn't notched. It's a lever that seems to work like a continuously varying slider.

2. There is a slight hum of the motor that seems to increase in pitch as the throttle is increased. Not loud prime mover sounds like that of a diesel locomotive but a light hum of an electric motor.

It'it has been suggested in another thread that there's also a constant blower sound.

We're looking for inputs possibly with examples as to what the prototypical operation of an electric locomotive would like. There's possibly variations in different electric types too. We would like to consider all suggestions.

Thank you.