[N&W] Re: Rock Slide Detector Fences

[nw-mailing-list at nwhs.org]

Bob,

  In my entire railroad career, I have NEVER seen a pile of rocks piled up 
behind a N&W slide fence., just a few that have been demed out of the way

  A typical slide fence usually(depending on length) has a minimum of three 
circit breakers that are operated by spring release, When a rock falls into 
the fence it will push the fence outward stretching the spring thus 
throwing the breaker and causing the entire block to be shut down with red 
signals on both ends. Then the dispatcher has to inform the local signal 
maintainer to patrol the track to find the problem,and then M-O-W to clean 
the way. During a windstorm, trees can be a pain in the rear on slide 
fences too!

The fences also work the other way to, when M-O-W cranes or equipment 
accidently bumps one and it isn't found until later when the dispathcer 
tries to set up the track for a movement.

But still definatly no piles of rock.

Gary Price

Gary Price at gpprice_nsc at yahoo.com
_______________________________________________________________________
I see small slides behind them (touching/piled up 2 or 3 feet) all of
the time between Northfork and Ennis. I was never aware that they were
supposed to do anything but stop small slides from getting on the track.
Bob Riffe leconte at inetone.net
_______________________________________________________________________
The slide fence is triggered by the falling rock/s pulling the fence out. 
It connected to a cable that goes to a signal box that turns the track 
circuit red. All the dispatcher would see is a red track circuit. the 
signal maintainer will have to go in and physically reset the slide fence box.

If the rock is big enough it to get stuck in the fence, it will have to be 
removed. Most just fall to the ground at the base of the fence. It would 
have to a huge rock slide to collect behind the fence. I have never seen this.

However, sleet and snow slides will trip the fence and they will collect 
there. This past winter there were many snow slides between Calera and 
Natural bridge. After they kept causing signal problems, a Gradeall was 
sent in the remove what snow they could behind the fences.

Yes, I have been stopped many times by a tripped slide fence.
Jimmy Lisle
_______________________________________________________________________
Good grief! Obviously some guys have a lot more time on their hands than I do!
John Black
Nashville, TN
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Bob,
I do not know you. But, your railroad gathering/discussion regarding rock 
fences reminds me of my own club. A sick bunch we are. Marvelous 
writing...I laughed my butt off. Sorry I cannot be of any help regarding 
the fences.
Jeff Rompala

ROCK SLIDE DETECTOR FENCES
 >
 > Some years ago while visiting a model railroad, one
 > of the members asked me about slide detector fences.
 > Locked in a not unusual model railroad mountain
 > predicament, the modeler was faced with very steep
 > -- almost vertical -- high embankments paralleling
 > his nicely curving mainline.
 >
 > Rather than mumble onward, I showed him several
 > slide detector fences in N&W and Clinchfield photo
 > books. For a modeler, I thought this was perfect as,
 > for me, there is no way better to model than directly
 > from proto photos.
 >
 > And he did.
 >
 > I was back there a month later and his slide fences
 > looked excellent, very close to the photos. Some were
 > in place while several others were formed and just
 > about ready to install. Nice job!
 >
 > Well, not so nice.
 >
 > I dropped in a few weeks later and about lost my lunch. All the slide
 > fences were in place and sceniced -- they looked great -- but between
 > the fences and the steep walls, the modeler had poured in enough rock
 > scraps to fill in the space about half way up his rock detector fence
 > and all along the full length of his excellent detecting wire web.
 >
 > Whaaaa?
 >
 > The modeler was thrilled with his work and merrily showed off all the
 > details, even including "... all the rock that over the years had
 > accumulated ..." behind the fence. He said he believed such a rock pile
 > was prototypical.
 >
 > Hummmm ...
 >
 > So, I asked him to show me a proto photo of slide detector fence holding
 > back that much rock. Of course, no such photo came to the limelight.
 >
 > However ...
 >
 > The situation stimulated an excellent debate (in which I mostly did not
 > partake) and which would have made cable TV's "Hardball" sound wimpy.
 > There were several interesting points made ... or should I say,
 > powerfully elucidated! The spit was flying ...
 >
 > Some swore the rock pile was realistic. Others made funny noises.
 >
 > Associating in favor of the rock pile theory, one said that railroads
 > used the fences to keep the rocks off the tracks ... And that no one
 > ever cleaned out the rock piles behind the fences.
 >
 > One fellow thought that to key the sensor a rock or slide had to break a
 > wire. Another said the rock hit the wire and it pulled a spring that
 > yanked a solenoid and set off the sensor. Most really didn't know.
 >
 > The voting was about even regarding the output. Maybe half said that
 > when hit the fence sensors triggered only red lights on the two nearest
 > signals guarding either direction through the slide area. But then, the
 > other half felt that the sensors sent a specific "fence-been-hit"
 > signal direct to the dispatcher. Futhermore, the other half didn't know
 > this one either.
 >
 > The fence takes a slant near the top and there were several opinions as
 > to why the slant and which way it slants -- toward or away from the
 > track -- photos be damned.
 >
 > There was more, such as how the fences look on each end, how many types
 > of sensors a given fence might have, how strong is the fence vs. the
 > size of the rocks that might fall, and are the fences typically painted
 > and what color? I'm sure there was more, but I'll cut it here so I can
 > make my point before I lose everyone.
 >
 > The modelers' discussion in reality was great. It brought up a variety
 > of railroad aspects that some had never heard of and in which virtually
 > all had some interest. I mean, this is the way railroad knowledge and
 > interest gets advanced. In spite of the shouts, the defending of turf
 > and even the volleys of misinformation, the debate was great.
 >
 > Years later we have email lists such as the one we are on now and on
 > which we can carry forth with the same sort of debate ... For the most
 > part, sans the red faces and with time to do a bit of research before
 > opening one's mouth ... Errrr ... Hitting the send button.
 >
 > What I'd like to do is to spread that debate here amongst this group. As
 > you read the material above you likely had an opinion or two on several
 > of the differing points. And I'm hoping you'll take the time to offer
 > here your knowledge and questions for both the modelers amongst us who
 > really would like to get it right and for the 1:1 fans here who just
 > like the warm fuzzies of learning more about real railroading.
 >
 > What do you all know about slide detector fences? Among several such
 > fences that I've seen are those up on the bluffs north of Clinchfield's
 > Copper Creek Viaduct (or was it a bridge? ... or a trestle?) and beside
 > the Norfolk & Western's Pokie mainline as it climbs the miles leading
 > to Maybeury (is that Ennis?). I only presume that the Virginian and B&O
 > had the rock stopping fences, too. What do you know?
 >
 > Frankly, I've never seen a slide fence back filled with rock. I've never
 > seen anyone carting away all the fallen stones. I've never seen a train
 > stopped by a red board induced by a slide fence. Heck ... The ones I
 > saw ... Well ... They were just standing there minding their own
 > business when I saw them.
 >
 > Sooooo ... What do you guys know? Spill your guts on this one ... Let it
 > all hang out. What's the low down on railroad slide detector fences?
 >
 > As a kickoff, why not check out this link to view a "Standard Rock Slide
 > Detector Fence (new type)" of May 8, 1975, on the D&RGW. But please do
 > not limit yourselves to modern era slide fences ... This is an "era
 > limitless" experiment.
 >
 > Click here:
 > 
http://users2.ev1.net/~swmeier/DRGW/MOWBooks/1966Book/images/Page%20156.1.jpg
 >
 > And here's a definition I found. Do you all agree with it? Does someone
 > have a better or corrected definition?
 >
 > >>>>>
 >
 > What is a slide detector fence?
 > To prevent train accidents due to falling rocks or earth slides in hilly
 > or mountainous regions, electrically charged wire fences are made to
 > serve as detectors. If a falling rock or an earth slide breaks one or
 > more of the wires in the fence, a relay is released and "stop" signals
 > are set up to halt a train approaching from either direction.
 > <<<<<
 >
 > Anyway, tonight I was thinking, "The Cubs lost ... Might as well do
 > slide fences." What do you say?
 >
 > Thanks and later ... Bob Loehne