Sound decoder for a 2-6-6-2 Mallet

[tstage]

Greetings all,

I recently picked up a brass NJCB NYC 2-6-6-2 Mallet that I'd like to eventually add sound to - i.e. once I ensure the motor brushes are isolated from the frame and wire the front headlight with a 0603 SMD LED.  The locomotive already has a can motor so that will make things a little easier converting it to DCC.

I generally use and prefer TCS and Loksound for my sound decoder installs because of the excellent motor control.  However, I read recently on here that the motor control with the Tsunami2 decoders is improved over the original Tsunami and am willing to give one of those a try.

From the Soundtraxx website, the new Tsunami2 TSU-Big Steam decoders offer three (3) non-Big Boy heavy chuffs vs TCS WOWSteam, which only has one heavy chuff offering.  Loksound is still pretty spartan with their American steam sound files offerings so I only use those for diesel sound installs.

So, my question for you all: Will any of the heavy chuffs available from either TCS or Tsunami be adequate for a 2-6-6-2 Mallet?

I've tried listening to a few recordings of actual Mallets while poking around YouTube and I've heard both synchronous and non-synchronous chuffs.  While it doesn't have to be spot-on, I would like the sound to be a reasonably good representation of what a Mallet sounds like in real life.

Thanks for the help in advance...

Tom

[gmpullman]

tstage

I've tried listening to a few recordings of actual Mallets while poking around YouTube and I've heard both synchronous and non-synchronous chuffs.

Others may have more information than what I can offer, Tom, and from what I gather the NYC NE-2 is a compound articulated. Therefore using the exhaust from the rear, high pressure cylinders fed into the larger, low pressure cylinders up front, then from there out the stack.

As such this engine's exhaust would sound just like any large locomotive (with lots more rod-clank, though) and the exhaust "chuffs" would not go in and out of syncopation.

https://www.american-rails.com/compound.html

I agree that ESU does fall short on their steam sound "projects. I have to recall if I've installed a Tsunami2 Steam decoder. I believe I do have one. The WOW sound is always a good choice for steam.

https://ctr.trains.com/photo-of-the-day/2018/04/nyc-2-6-6-2-in-west-virginia

Probably the only operating compound Mallet operating in the U.S. today is #7 "Skookum" built for the Deep River Logging and later the Columbia River Belt Line.

Unfortunately, she never really works hard enough to hear a good exhaust sound.

I did come across this excellent recording of Black Hills Central working up a 6% grade, now this should give you a pretty good idea of what your NE-2 sounded like 

Congratulations on your new roster addition 

Good Luck, Ed

[Overmod]

There is a documented 'tendency' for Mallet-chassis exhausts to 'fall into sync' as the engine works.  There are physical reasons why this might be so, including why true Mallets have less runaway-slip problem when starting or working a heavy train; there are also people who believe the effect is partly perceptual.

Keep in mind that almost any true American Mallet will use an intercepting valve for starting.  In practice this was supposed to admit a smaller quantity of boiler-pressure steam to the LP at starting and low speed so the two engines would develop equal torque (and neither, therefore, would tend to slip before the other) but in practice you see people get greedy and try to get highest possible TE by admitting full-pressure steam without limited-cutoff arrangement to what may be large cylinders.  In any case the switch to compound has to come pretty quick as otherwise 'steam production runs out quick' with the colossal mass flow.  Note that the intercepting valve system also often has special exhaust connections which would radically alter the sound when the intercepting valve is open.

There is also often a bypass system on the LP cylinders, for drifting, as otherwise there would be terrible action tending to nose or hunt the hinged engine.  This was carefully documented and explained at some point in the restoration of C&O 1309.

I don't see how you model a locomotive like this without two separate decoders, with very separate programming -- in fact, without very special speed- and time-related programming for the LP engine -- and perhaps some careful thinking about whether you want 'hard' timing on one or both engines (e.g. with magnets, limit switches, and careful ritation counting in the driveline, or cams/optical encoders) vs. synthesized "chuff" timing and phasing based on speed increase or back EMF 'data'.

Here's the fun point: when the engine works compound with the intercepting valve closed, there is relatively little sound from HP cylinder exhaust -- as with the condensing Henschel class 25 4-8-4s in South Africa -- going into the receiver instead of out the stack making noise.  So you'd get possibly-syncopated clanking from the two sets of rods, as if for two engines, but only exhaust sound for one, and that a bit muted compared to typical HP-engine exhaust.   You might 'get by' with just one decoder making LPish noises if you could double the mechanical-noise speed -- and handwave the complex stuff supposed to happen at starting where there would be two exhausts.

Something you'd almost never get, though, are N&W A-class-style 'double licks' -- equal exhaust sound from two simple engines in variable phase.  This seems to be what many steam decoders seem to use when simulating an "articulated locomotive" but it will NOT do for a Mallet  ... except at starting.

[tstage]

Thanks, Ed.  Yea, I ran across that same video clip last night when I was poking around Youtube.

The Tsunami2 "Heavy 3" exhaust chuff seems like it might be a good fit.  I'm assuming you can switch out the whistles for alternative ones like you can Loksound and TCS decoders?

Thanks,

Tom

[wjstix]

FWIW I have a TCS sound decoder in my Bachmann USRA 2-6-6-2 and it sounds good to me. 

As Ed said, the NYC N class 2-6-6-2s were 'true' (compound) Mallets, so you would use the normal 4-chuffs-per-revolution setting on whichever sound decoder you choose, not the 'articulated' "chuff-chuff......chuff-chuff......chuff-chuff" setting that's meant to simulate a simple articulated where all four cylinders exhaust directly to the smokebox/stack.

[tstage]

Thanks for that bit of info, Stix. Yea, my limited understanding about Mallets is pretty much what Ed wrote earlier - i.e. that the smaller, high pressure cylinders exhausted into the larger, low-pressure cylinders then out the stack.

Waiting patiently for UPS to deliver the Mallet.  Will post a photo or two when I have a chance to unwrap it and take it through its paces.

Tom

[richhotrain]

wjstix

FWIW I have a TCS sound decoder in my Bachmann USRA 2-6-6-2 and it sounds good to me. 

As Ed said, the NYC N class 2-6-6-2s were 'true' (compound) Mallets, so you would use the normal 4-chuffs-per-revolution setting on whichever sound decoder you choose, not the 'articulated' "chuff-chuff......chuff-chuff......chuff-chuff" setting that's meant to simulate a simple articulated where all four cylinders exhaust directly to the smokebox/stack. 

I am glad you posted that info, Stix. I was debating whether to ask about the Bachmann Spectrum 2-6-6-2 on this thread or start another thread. I have had a Bachmann Spectrum 2-6-6-2 for years but it is no-sound. I want to convert to a sound decoder. Is TCS the way to go?

Rich

[tstage]

Well, here's the new beauty & beast: (Click photos to enlarge)

I spent some time this past evening breaking her in on the roller bearing stands at various speeds - forwards and backwards.  There's a tiny bit of hesitation and wobble at low speed.  However, the wobble may be primarily due to how it rides on the roller bearing stands, as I could have used another set of four: Two under the center drivers and one under the lead & trailing trucks for support.  A good cleaning and re-lubing will also help smooth things out.

Tom

[richhotrain]

Wow, what a thing of beauty. I have a Bachmann Spectrum 2-6-6-2, one of my three favorite steam engines, but nowhere near the level of detail shown on that brass beast. Nice purchase, Tom.

Rich

[gmpullman]

tstage

Well, here's the new beauty & beast:

I am green (or is that two-tone gray?) with envy, Tom, yet absolutely thrilled that you have that beautiful monster living with you! Talk about a centerpiece in your roundhouse.

Now how about 50 or 60 NYC fifty-ton hopper cars so she'll be able to feel useful 

I believe I have an old NYCHS Headlight around with some information on these. I'll take a look this weekend.

NYC_NE-2 by Edmund, on Flickr

Regards, Ed