Right, Steemtrayn.
On prototype simple articulateds (like the N&W Class A) and duplexes, the front engine and rear engine often ran out of sync because one engine had more slippage than the other, the steam pipes were different lengths, tire wear was uneven, etc. Sometimes the front and rear pistons and valves were different sizes. In the case of the PRR, the Q2 freight duplexes were known to run in and out of phase regularly. This effect can be replicated in two ways that I know of: separate motors and drive trains for each engine, or a clutch of some kind that allows for some slippage in one engine. I believe both approaches have been tried in models. In fact, I seem to recall that the original Penn Line T1 had two motors. This would require cams on at least one axle of each engine. There may be a way to accomplish this electronically, but that's beyond my pay grade.
Tom
If the front and rear mechanisms are both coupled to the same motor, wouldn't the second cam installation be a waste of time?
Dave
Just be glad you don't have to press "2" for English.
http://www.youtube.com/watch?v=zQ_ALEdDUB8
http://www.youtube.com/watch?v=6hqFS1GZL4s
http://s73.photobucket.com/user/steemtrayn/media/MovingcoalontheDCM.mp4.html?sort=3&o=27
From my experience, the BLI chuff sensor (reed switch) is set to pick up from a magnet embedded in the flywheel. I suppose you could set another magnet and reed switch but I'm only aware of decoders that have one input for the sensor.
I have a brass NYC Mohawk that has a square-lobed cam on a driver axel and I installed a wiper to pick up the exhaust count there.
If you fix sensors on the axel or drive shaft they will always be "in synch" with eachother. The compound engines still only had an exhaust chuff every quarter revolution since the exhaust from the high pressure cylinders didn't go out the stack but was directed to the low pressure cylinders.
In a simple articulated like your 2-6-6-4 or the UP Big Boys where both sets of engines use high pressure steam and exhaust to the stack (or stacks) they would sometimes run in-synch or out of synch depending on rail conditions, curvature or adhesion.
Both Wowsound and Tsunami have selections for "articulated" and I'm pretty sure there is simple and compound selections in the Tsunami but I can't say for sure about the WOW sound.
Articulated has more to do with the mechanical coupling of the sets of drivers than it does with steam usage. That complicates the issue when talking about exhaust sounds.
Go to page 45 here and there is a pretty good explanation of Tsunamis exhaust settings:
http://www.soundtraxx.com/manuals/tsunamisteam_users_guide.pdf
The PRR T1 is a duplex engine but it is not articulated.
On any of the duplex locomotives that I run it seems like the sound is just a machine-gun staccato at speeds above 25 or so. Simple or compound duplex.
Some things just don't scale down to our size too well. Duplex exhaust sound is one of them.
Have fun, Ed
TrAcKr76 Hey y'all, I was just wandering if it is possible to install dual chuff cams in the front and rear driver sets on BLI N&W 2-6-6-4. I was also wandering, if I am able to install these, will the TCS WOW Sound be able to take 2 cams? Thanks.
Hey y'all, I was just wandering if it is possible to install dual chuff cams in the front and rear driver sets on BLI N&W 2-6-6-4. I was also wandering, if I am able to install these, will the TCS WOW Sound be able to take 2 cams? Thanks.
You could theoretically do this. But a number of cam wheel kits come with options for compound, simple, and logging locos.
There's only 1 wire connection to the decoder for the chuff. Soundtraxx sells a cam kit commonly available:
http://www.soundtraxx.com/access/wiring.php
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Indianapolis Railroad - Indy Rail! Route of the Brickyard Flyer! Established 1976.