Lionel Diesels with Railsounds

Frightfully easy, just flick the RS/SS switch to the SS position and the prime mover sounds will go away.  If you don't have the switch on the locomotive, just jumper pin 15 to pin 17 on the RailSounds board, job done.  They're right next to each other, so it's pretty easy.

With the exception of recent production covering the past few years, there should be a RailSounds/SignalSounds switch on just about all Lionel RailSounds locomotives. Simply moving the switch to the SignalSounds position will cause the background sounds to drop-out, while still keeping the horn and bell sounds at whichever volume you set with the volume potentiometer.

I believe the switch was eventually eliminated, as the function can be accomplished by lowering the volume (to zero) with via TMCC or Legacy, while maintaining the full volume of the horn and bell sounds.

TRW

  Shhh! Don't make any noise while the music is playin'. I don't like any noise when the music is playin'.. ..  either.

I don't think you can silence everything,  But you can tone it down in a way without loosing whistle/bell.

You should be able to stop the chuff by simply removing the wheels/axle with the magnet or cam, or uplugging the sensor microswitch. If the chuff sounds non-stop the switch leads would need to be jumped together.

You might still have steam idle pressure relief sounds and crew talk "ready",call it a night", etc.. It doesn't get old fast like the "static" of chuff thru a speaker. The cycling is slow and soothing, kind of like the bubbling oil well's pump; a slow, even, metronome /clock pendulum-like speed ..click..clack......click..clack.......

 In diesels and elecrtric you would likely still have idle and electrics; fans, but no rpm ramping, etc.

I run conventional and keep a tender on a siding nearby so "everything" can have whistle /bell. I also have a Tyco billboard whistle doubling as an industrial hvac unit on a roof so even tin plate nights have some variety.

  (it was free, I wouldn't buy one. Buy big name O whistle shacks & billboards; much better)

That post sat for an hour. 

Darn in John, now that I know the pins, I'll end up wiring a switch in

John:  Found switch, and switched it off.  Now there is only a horn and a bell.      Thanks.