My LHS had an Atlas Gold locomotive (9661). It's a GE Dash 8-40C.
Anyone know about the sound decoders in this unit?
One sound I'm looking for is the air system "spitter" sound. These locomotives often make the noise while idling. I was wondering if anyone is aware if these models include that effect, and if not - are there any after market decoders that do?
It'd be great if some site allowed people to listen to the sounds included in decoders and compare them.
If anyone has input I'd appreciate it. :)
That would be a QSI decoder in there. I'm pretty sure they have the sound you're talking about, when sitting idling, there is a periodic air relase, which is the drain **** popping off and releaseing accumulated water from the air line.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
NSColsMP6 My LHS had an Atlas Gold locomotive (9661). It's a GE Dash 8-40C. Anyone know about the sound decoders in this unit? One sound I'm looking for is the air system "spitter" sound. These locomotives often make the noise while idling. I was wondering if anyone is aware if these models include that effect, and if not - are there any after market decoders that do? It'd be great if some site allowed people to listen to the sounds included in decoders and compare them. If anyone has input I'd appreciate it. :)
I have this unit and "yes" it is a QSI sound decoder and has the random sounds such as the air release.
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rrinker That would be a QSI decoder in there. I'm pretty sure they have the sound you're talking about, when sitting idling, there is a periodic air relase, which is the drain **** popping off and releaseing accumulated water from the air line. --Randy
I've heard people say the sound is made by "the spitter". It happens on average about once per second and kind of sounds like a random ticking sound of popping air. The UP engine 27 seconds into this video captures the sound I'm looking for: http://www.youtube.com/watch?v=0w717GeZhTA
That's why it's called the 'spitter', it spits out water. When you compress air, moisture condenses out. Water does not compress like air does, nor is it good for the insides of brake pipes, valves, and cylinders. So there is a water seperator after the compressor that pulls the water out. Periodically a valve opens to release the collected water. Most modern trucks and busses have them as well. It is also the reason why on older locos the air tanks were often mounted in a V shape, the water would collect at the low point in the air tanks and could be drained out by a manually operated valve.
rrinker That's why it's called the 'spitter', it spits out water. --Randy
That's why it's called the 'spitter', it spits out water. --Randy
Yeah, I know what it does - I'm just trying to find out which DCC sound decoders include that sound.
A friend of mine also mentioned a "WHOOP" sound that he's been told is caused by computerized slip control on the traction motors.
Just to avoid confusion, the moisture expelling "spitter valve" and the air "pop off" are two seperate functions.
Crude, simplified version of air pop off:
Air let off or "pop off" occurs once the air compressor has filled the locomotive's air tank(s) to maximum capacity (120 psi in many older units). The excess air is expelled through a valve that opens, then closes once the pressure inside of the tank is at its normal setting. Hence the loud, random "tssssh!" sound so many of us are familiar with. Many diesel powered trucks and buses with pnuematic brakes have this feature as well. Often times as the components age, including the valve which may stick slightly, the pop off sounds becomes longer. On older locomotives If the pop off valve becomes stuck, opens too slowly, OR if the compressor's sensor doesn't turn it off after air pressure has reached maximum and allows the compressor to continue pumping, something will give! There was a photo on railpictures.net showing a Dash 2 EMD with a twisted, ruptured tank resulting from "overpumping".. The locomotive's frame was actually bent. If I can find it again, I'll post it. Newer units have built in safeguards to prevent that from happening.
I've listend to sound equipped units in person and on the web. Have not heard any with the spitter valve feature. I have the QSI Q2 programmer on my PC and have sampled nearly all of the diesel sound schemes and haven't seen this feature. However, you have me curious and I'm going to check again. Would be a neat feature.
Not too long ago I saw a stopped CSX mixed frieght with a GP40-2 in the lead. The engineer was waiting at a red signal. All 3 of his units were "spitting" loudly and fast.
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NSColsMP6 A friend of mine also mentioned a "WHOOP" sound that he's been told is caused by computerized slip control on the traction motors.
That "whoop" sound is the sound of the motor driven air compressor starting. My Atlas B23-7 has that sound. I think that sound is actually incorrect for the B23, which I've been told had a compressor driven by the diesel engine (or a belt from), not by a motor. Nevertheless, it is a fun sound that never stops bringing a smile.