I found a dutch article where someone used it for a train. These modules are super cool.
You need an additional amplifier. The files can be selected in several ways (depends on the firmware) With a sd card that can hold files and a new firmware that looks pretty useful.
The Dutch guy stated the power of the amplifier caused issues he said the module is "sensitive"
Out of the box the firmware stops the playing sound when a new sound is requested. He changed the firmware so he could mix up to 4 sounds.
Yes I want some. you can count me in
Jantje