Looking for sound

Model Railroader Electronics and DCC
1

I am looking for a specific sound of which I will try to describe. I want to see if I can program it into my AC4400’s using Digitrax SDH104K1A+FN04K1 COMBO decoder.

While I was watching a youtube video I beleive the AC4400 was sitting still and it almost sounded like a brake or air release of some kind…

It was a very short spitting sound or clicking sound and happened about every 2 or 3 seconds.

I’m not sure what I’m looking for nor can I find the video I was looking at !

Any thoughts would be appreciated![um] (In case of spitting).

2

Usually that is the air pump cutting out. Check the manual for your decoder. Digitrax has the manual. All the air pumps I have ever worked with do that.

Rich

3

I believe what you’re looking for is called a spit valve – it releases air from the tank in very short bursts when the pressure gets too high.

4

I believe that what you’re describing is the automatic condensation drain valve that the big GE’s are equipped with.

It sounds almost like a large electrical arc or zapping noise.

From what I understand, it doesn’t so much limit pressure in the reservoir (the cutoff on the compressor does that), but rather it just eliminates the need for someone to periodically perform a manual process to drain the condensation.