I regularly hear intermittent “ticking” noises coming from locos, usually at low speeds. Anyone?
I’m thinking what you’re hearing is the air valves popping
It sounds like the Spitter valve dumping Water from the air supply
Air compressors compress the outside air along with its moisture. The atmosphere is typically 1% water vapor and this condenses in the lower parts of the high pressure air systems. To prevent the water from building up, the air system has blow down valves on the bottom of air reservoirs and at the low points in the piping. These open electrically on timers and dump a little air and the condensed water out of the bottom of the tanks and pipes.These valves can cause a clicking and usually a blast of air (directed downward) every couple of minutes.
In addition, there are check valves between the various air reservoirs such that if there is a rupture in the supply lines and first tank, air won’t leak back from the second tank. That valve also clicks when the air compressor is moving air into the tanks.
A third clicking is the hand brake chain swinging back and forth in the tube leading down from the hand brake ratchet.
So there are the more probable clicking sources.
BINGO…you win the “cupie doll” prize. I hear this almost exclusively on GE units and at times the “ticking” noise of the valve opening and closing are once every second or more.
Well, I’m positive it’s not exclusive to GEs, I used to railfan C&NW in the early 90s in River Forest IL. and there was quite often a transfer heading to Proviso with a company SD40-2 and a Conrail SD50 both with valves-a-poppin.
I’ve been seeing my neighborhood local freight (pun intended) up close a lot of late. It is a Providence & Worcester job that typically operates with 2 locomotives, generally either 2 GP38-2s or a GP38-2 and a GE Dash 8 (either an 8-40B or an 8-39B).
Both makes/models click and tick plenty and I’m sure it’s the air brake system making the noise…
Listen, while we’re on the subject of diesel noises when I’m trackside and a diesel locomotive passes at slow speed, or sometimes while accelerating I hear a noise that sounds like “Wooo-OOOOP!” coming from the unit. Anyone know what that is?
Are you referring to GE units? GE locomotives built within the last 20 years or so make that noise. I believe it’s the belt on the air compressor engaging, but I could be wrong.
To wholeman: yes, they are GE units, haven’t noticed the noise coming from EMDs. Thanx for the response!
Yep, spitter valves. Don’t want water in the air line!
That Whoop is in fact the compressor kicking on.
We really ought to have a railroad sounds faq, because the SPitter valve and the GE compressor Whoop are pretty common questions on here. Not that I mind answering them when I can, but it would be nice to have a place for people to get the answer themselves.
Thank you YoHo1975. And you’re right, a “What’s That Noise?” glossary would be handy.