VGN 2-10-10-2 - my 2014 challenge

[jwb]

This engine is a mallet, an compound engine. If it should I add a sound decoder then you will hear only the chuff-chuff of the front engine. The rear cylinders deliver the exhaust steam to front cylinders and you will hear ... What? Maybe an acoustic noise, also in a rhytmic sequence but not a clear chuff-chuff. This will only come from front cylinders.

Actually, it suddenly dawned on me a couple days after you posted this, I was thinking about the sound on DVDs of Norfolk and Western steam. There's basically no difference in what you hear between a Y6b, a compound, and an A, which is simple. I believe the reason is that the Ys started in simple and changed over to compound above a certain speed. I simply don't know if this applies to all compounds, although definitely some German compounds, like Borries, did work this way. Nor do I know if this applied to all US Mallets.

There are a couple of interesting issues here. One is that if you say I'm running my Mallet as a compound for sound decoder purposes, fine, you just use a simple single-loco sound unit. Great, no problem over the question of the units going in and out of sync. On the other hand, you have an interesting problem with sound on a Mallet: if it starts in simple, you use an articulated decoder that goes in and out of sync -- I think any decoder for UP, DM&IR, B&O, etc modern locos would apply. But even if the loco shifts to compound over a certain speed, the exhaust chuffs by then are coming out fast enough that you probably can't tell the difference there, either.

I have one of those early Powerhouse hybrid USRA 2-8-8-2s that I'm slowly working toward making for a Virginian USA, not ruling out the original "US" lettering, and now that I think of it, maybe I should look more closely into the simple vs compound issue.

For that matter, I have one of the BLI Erie Triplexes, and it has an in-and-out-of sync decoder, which I suspect is correct for any speed where you can differentiate the chuffs. A bigger problem for me is the Westinghouse air pump sound, since these locos had New York air compressors!