From: johnm@hpmcaa.mcm.hp.com.mcm.hp.com (John Mosbarger)
Subject: Re: Talking Detectors
Organization: HP Cardiology Business Unit - McMinnville, OR
X-Newsreader: TIN [version 1.1 PL7]
Date: Wed, 16 Dec 1992 20:42:06 GMT

Tom Vervaeke (tvervaek@col.hp.com) wrote:
: 
: I have several questions regarding railroad track detectors. My local
: timetable mentions three kinds: talking, non-talking, and talk on  
: defect only. Since I know nothing about this topic also I'm going to ask
: for some more help from fellow netters:
: 
: 1. Talking Detectors: I assume they talk by broadcasting on a specific
:    frequency. What is this frequency? Does it vary or always the same.
:    My timetable makes no mention of how to listen in.

     They broadcast on the road frequency in order for the crew to know
what's happening.  There are several types of "talkers";  dragging equip-
ment, hot box, hide/wide load, loose wheel come to mind.  UP & SP detectors
give the milepost and BN's give a location (the ones I've heard are the
nearest town).  A typical SP detector message is:  "SP detector, milepost
XXX.X, no defects.....no defects."  UP's are:  UP detector, milepost XXX.X,
no defects.....no defects.....think safety.....detector out."  I've heard
some of BN's detectors also give the outside air temperature.

     BTW, the talk-on-defect only detectors are quite annoying to the rail-
fan trying to locate a train knowing the location of the detectors.  UP in
the Feather River Canyon is 1 example.

: 2. Non-Talking: How do they communicate? Could I assume via a wire
:    to the dispatcher?

     Usually a revolving red light.  When the light comes on the train must
stop and the crew must stop and inspect the entire train, since there is no
axle count with these kind.  The head-end crew will call "Dragger right/left,"
and if there is no defect, the conductor in the caboose will call out "Black
dragger."  And since there are very few trains with cabooses, there are also
very few of this kind of dragger remaining, as well as the detectors with
the digital readout that displays the axle count.

: 3. What kinds of items do they report? I've heard of hot-box, items 
:    hanging, etc.. Are there others?

     See answer to #1.

: 4. How would I recognize one if I stumbled along the tracks and hit one?
:    Do they all have a similar shape, etc..? 

     The dragging equiment detectors use an a-shaped piece of galvanized
metal mounted crosswise with a wire also running crosswise underneath.
Anything below the railhead will hit the sheet metal and force it down to
contact with the wire.  The detector (SP's) will call out:  "SP detector,
milepost XXX.X, Stop your train!.....Stop your train!....dragging equipment."
Some detectors will also call out the axle count.  This info is also noted
on the dispatcher's board.  Some of the newer detectors are of the self-
resetting type as opposed to the kind that require a signal maintainer to
manually reset.

: Any information would be appreciated. I'd like to thank all the
: knowledgeable folks out there who always chime in and help me out. As a
: beginning railfan I find your posts to be worth a lot. I have a large
: folder of them and am thinking about penning a "Railfanning Starters
: Guide" someday soon (perhaps this winter).

     Start a railfan FAQ.  I'd like to know what I've said in the past and
if I've learned anything over the years :-):-).

John
--
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| John Mosbarger          |    You know why many people commit suicide      |
|                         |    during the holidays?  It's because they're   |
| HP McMinnville, OR      |    forced to spend time with their relatives.   |
|                         | 	                  --John Belushi            |
| johnm@hpmcaa.mcm.hp.com |                     	                    |
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|                     Opinions are mine and mine alone.                     |
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