Bug? Steam train sounds like Internal Combustion Engine

Unlike combustion-engine powered vehicles, Steam train would not "chuff" when stopped. The only thing that might sound like a chuff when stopped is the piston-powered air compressor, which sounds different and are separate from the driving piston.
As it is right now, how the sound is implemented in the game right now does not make sense. I imagine the easiest thing to implement might be to simply mute the chuff when the speed is 0, with gradual ramp up in volume when it starts moving. It will still not be very accurate but at least it's better than it is right now, without getting too much into details on how a steam train's chuff should sound like.
I do hear a separate sound that sounds like steam hissing around when the train is stopped, so maybe if the train is stopped and it is the only thing that sounds, it would sound great already.