The snifter valve is opened on stationary steam locomotives to allow an escape of steam build up before it builds up in the cylinders. If residual steam gets past the throttle valve it can also get into the cylinders causing the locomotive to roll. If enough steam gets into the cylinder it could even over power the brakes holding it. The snifter valve is not controlled in the cab. They are in the main steam pipe going to the cylinders. What Soundtraxx is calling the snifter valve I believe is actually the power reverser. The reverser is air powered on later steam locomotives. Another noise that could be heard before a locomotive starts moving is the cylinder cocks being opened. These are drain valves on the under side of each cylinder to allow condensed water to drain and escape before damaging a cylinder. There is also an air bleed down from the brake cylinder on release of the brakes. Steam locomotives made all kinds of noises.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
I went to the link provided by Cacole (thanks Cacole), and went from cv to cv programming them to zero until I got to the sound I found annoying. It was the snifter valve. When I turned it to zero, the sound was gone. I also took the time to turn the brake squeal volume down. Now Im pretty happy with everything.
I believe the Tsunami steam decoder has a sound - more of a 'clank' than a "cha' in my opinion - that represents the sound of the throttle being pushed open by the engineer, to allow steam into the cylinders. If that's the sound you're hearing, it is prototypical but might be set too loud. All the Tsunami sounds have volume CV's I believe so you should be able to turn it down so it's less noticeable. (I think it's a sound you might have heard in real life standing near the engine, but not from a distance, so it shouldn't be very loud.)
Does this loco have factory installed sound? If so, it's a Tsunami decoder and you need to download the complete manual from the SoundTraxx web site.
http://www.soundtraxx.com/factory/OEM%20pages/Bachmann/Bachmann.php
Without actually hearing the sound you mention, it's impossible to know what it is.
First of all, Id like to say, I love this engine. Its my favorite steam loco, thats why this problem is so distressing to me. My loco is DCC with sound. When I advance the throttle to the first speed step theres an abbreviated "cha" sound and a slight hesitation. This only happens when I go from a standstill to the first step. Is this a flaw or is the sound supposed to be there? Im not the most knowledgeable in the area of steam engine sounds. Is there any way to eliminate this?