What is the stacotto spitting sound that I hear from locomotives (especially 2nd generation EMD units) when they are idling or at low speed?
Tom
Original Post
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wheel greaser
Thanks. It would be neat if Lionel and MTH included this sound with their diesels.
Tom
I believe the sound to which the original poster is referring is part of the air system. Many locomotives are now fitted with air dryers with automatic valves to vent water and moisture which has condensed within the system. When activated, this valve emits a "spitting" sound as the moisture is discharged.
Bob
It is a water eliminator for the air system. They are automatic in nature. They're located in a low point of the air piping system on the locomotive and when the small reservoir fills with water they open for a second and spit the water out.
Ron
Originally Posted by RailfanRon:
It is a water eliminator for the air system. They are automatic in nature. They're located in a low point of the air piping system on the locomotive and when the small reservoir fills with water they open for a second and spit the water out.
Ron
It's an automatic drain valve.
The ones on our locomotives are automatic and work the same way an automatic condensate valve works on a steam heating system. When the holder fills up the valve opens and exhausts the water. When they are empty (about a second or less) they close automatically. Thus they sound like they're spitting. They have no connections other than being tied to the air line.
Ron
765 will soon be equipped with these spitter valves to help dry the air.
