News wire article on problems getting crossing to shunt. Tried to post part about ground conductibity. Link is here.
M3 Map of Effective Ground Conductivity in the United States for AM Broadcast Stations | Federal Communications Commission (fcc.gov)
The quest to counteract 'loss of shunt:' Special Report - Trains
Axle.
Editor Emeritus, This Week at Amtrak
I have no idea of what is inadequate in the signal systems of those carriers that are requiring 32 axles.
Amtrak has been operating the Capitol Limited for the past year or so between Chicago and Washington with 20 axles. Engine, baggage car and three passenger cars.
B&O and subsequently CSX restrict single engines to 30 MPH as at higher speeds, the equipment can move through the circuits faster than realys could react. Of course, the newer generations of signal equipment have done away with relays and replaced them with electronic circuits - which to my mind should activate faster than relays.
Never too old to have a happy childhood!
BaltACDI have no idea of what is inadequate in the signal systems of those carriers that are requiring 32 axles. Amtrak has been operating the Capitol Limited for the past year or so between Chicago and Washington with 20 axles. Engine, baggage car and three passenger cars. B&O and subsequently CSX restrict single engines to 30 MPH as at higher speeds, the equipment can move through the circuits faster than realys could react. Of course, the newer generations of signal equipment have done away with relays and replaced them with electronic circuits - which to my mind should activate faster than relays.
Way back in the 1980's the Milwaukee Road had that issue on the Milwaukee to Watertown section of their twin cities mainline. They feared the whole lack of ability to shunt for a single Budd SPV2000 and they added an additional passenger car to the end of it that didn't carry passengers (non-HEP). In the Milwaukee Roads case it was an old signal system I suspect because since CP has upgraded it and single self propelled cars are no longer an issue as they used an old RDC to inspect the line at one point.................so I am going to go out on a limb here and suggest it might be the same issue with the former IC.
What's unacceptable, in my view, is that Amtrak let this axle count nonsense go on. The host imposed something unreasonable. They should be on the hook to fix it and pay the costs in the mean time.
What Amtrak did that is almost as bad, is not try to make lemonade from the lemons. Make the extra cars mostly coaches, pay for an extra crew person or two, and adjust fares to fill up the trains.
And, they would have had the coaches if they hadn't purchased so many baggage cars instead of coaches (or at least combines...)
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Lets begin at the beginning. Take a look at what is happening when no trains are in the circuit. Did the RRs in the past or now have false shunts that activated the signals? If so, are there closer tolorences between false shunts and no shunt when train is on the circuit? Is this due to the ground conductivity being much higher CHI South and to West? See link below for conductivity. If so what measures are implemented by the signals personnel? Does signals department change activation values to where light weight equipment does not activate signals?
1. there have been no reports of the rebuilt CHI - St. Louis tracks having any shunt problems. Can that be because of clean ballast and concrete ties?
2. Could blowing higher conductivity ground debri foul ballast to allow false shunts on empty track?
3. Does rail grinding leave enough steel dust to increase probability of false activations?
4. What is the last time that ballast has been completely cleaned especially costly undercutting?
5. What is ballast depth compared to other locations?
6. Are wooden cross ties different to allow more conduction?
Why is it Brightline in a somewhat higher ground conducctivity area is not having any reports of non shunting on the West Palm Beach - Cocoa segment when using its lightweight trains testing the signal system?
blue streak 1 Lets begin at the beginning. Take a look at what is happening when no trains are in the circuit. Did the RRs in the past or now have false shunts that activated the signals? If so, are there closer tolorences between false shunts and no shunt when train is on the circuit? Is this due to the ground conductivity being much higher CHI South and to West? See link below for conductivity. If so what measures are implemented by the signals personnel? Does signals department change activation values to where light weight equipment does not activate signals? 1. there have been no reports of the rebuilt CHI - St. Louis tracks having any shunt problems. Can that be because of clean ballast and concrete ties? 2. Could blowing higher conductivity ground debri foul ballast to allow false shunts on empty track? 3. Does rail grinding leave enough steel dust to increase probability of false activations? 4. What is the last time that ballast has been completely cleaned especially costly undercutting? 5. What is ballast depth compared to other locations? 6. Are wooden cross ties different to allow more conduction? M3 Map of Effective Ground Conductivity in the United States for AM Broadcast Stations | Federal Communications Commission (fcc.gov)
If memory serves me correctly, false shunts require a connection between both rails and could be achieved with one of those metal straps they used to secure lumber with. The problem is that it will not shunt just by laying it across the rails you need someone to stand on each rail and rub the metal strap with their foot in order to activate the crossing signals...........or so I heard from somewhere. I have never actually done it myself. I think with more modern relays and electronics the old lumber strap technique probably won't work, that was back in the 1970's when it did work last I heard. So again I suspect the shunting issue is due to old equipment/electronics/wiring that IC/CN has not updated.
Also, I have read that signal maintainers use shunts all the time in their maintenence of crossing signals and probably do the same with traffic signals. I think you need access to the the actual relay or electronics cabinet near the signal or crossing to pull that off and you also need to know where to hook it up to........but I suspect the railroads have the connection points clearly labeled in some cabinets........just a hunch given their tendency to label obvious items like the military does.
CMStPnP blue streak 1 Lets begin at the beginning. Take a look at what is happening when no trains are in the circuit. Did the RRs in the past or now have false shunts that activated the signals? If so, are there closer tolorences between false shunts and no shunt when train is on the circuit? Is this due to the ground conductivity being much higher CHI South and to West? See link below for conductivity. If so what measures are implemented by the signals personnel? Does signals department change activation values to where light weight equipment does not activate signals? 1. there have been no reports of the rebuilt CHI - St. Louis tracks having any shunt problems. Can that be because of clean ballast and concrete ties? 2. Could blowing higher conductivity ground debri foul ballast to allow false shunts on empty track? 3. Does rail grinding leave enough steel dust to increase probability of false activations? 4. What is the last time that ballast has been completely cleaned especially costly undercutting? 5. What is ballast depth compared to other locations? 6. Are wooden cross ties different to allow more conduction? M3 Map of Effective Ground Conductivity in the United States for AM Broadcast Stations | Federal Communications Commission (fcc.gov) If memory serves me correctly, false shunts require a connection between both rails and could be achieved with one of those metal straps they used to secure lumber with. The problem is that it will not shunt just by laying it across the rails you need someone to stand on each rail and rub the metal strap with their foot in order to activate the crossing signals...........or so I heard from somewhere. I have never actually done it myself. I think with more modern relays and electronics the old lumber strap technique probably won't work, that was back in the 1970's when it did work last I heard. So again I suspect the shunting issue is due to old equipment/electronics/wiring that IC/CN has not updated. Also, I have read that signal maintainers use shunts all the time in their maintenence of crossing signals and probably do the same with traffic signals. I think you need access to the the actual relay or electronics cabinet near the signal or crossing to pull that off and you also need to know where to hook it up to........but I suspect the railroads have the connection points clearly labeled in some cabinets........just a hunch given their tendency to label obvious items like the military does.
Banding CAN shunt track circuits, especially if the banding comes off, straddles the rails and then is 'run into' the rails by a passing train. This can also happen if the banding gets tangles up with the rail/tie plate interface on both rails.
The most common happening in my 26 years of being an Asst. Chief Dispatcher was logging track circuits that stayed on AFTER trains had cleared the limits of the track segment the circuit represented. Yes, most of these track circuits were left on by broken rails and/or pulled apart rail joints; that being said there were also any number of incidents of metalic debris shunting the circuits.
Whenever a track circuit remains on and it should be off, a Signal Mantainer and frequently Track Inspector are dispatched to investigate and resolve the problem.
A situation that did happen when signals were installed on previously dark territory that had used steel mill slag as the ballast. The metalic residue in the slag was sufficient to create a shunt when rails wore against the slag. Those territories were upgraded to 'genuine' granite or limestone ballast that was not electrically conductive.
oltmanndWhat's unacceptable, in my view, is that Amtrak let this axle count nonsense go on. The host imposed something unreasonable. They should be on the hook to fix it and pay the costs in the mean time. What Amtrak did that is almost as bad, is not try to make lemonade from the lemons. Make the extra cars mostly coaches, pay for an extra crew person or two, and adjust fares to fill up the trains. And, they would have had the coaches if they hadn't purchased so many baggage cars instead of coaches (or at least combines...)
Take 3 or 4 Viewliner bags, paint them white, and install shackles?
Or just take a nod from the liner industry and establish a new 'steerage' class. Ideal place to put modular hostel-style multiple-level bunks (with little flatscreens for the "window" effect).
Come to think of it... pity they've gotten rid of the MHCs; they could establish 'package and express' service at low, low prices and say "you made me do it" when the railroad tries to complain...
/
How does that Bon Jovi song go? "Shunt to the heart and your to blame, baby you give railroad signals a bad name...."
BaltACD A situation that did happen when signals were installed on previously dark territory that had used steel mill slag as the ballast. The metalic residue in the slag was sufficient to create a shunt when rails wore against the slag. Those territories were upgraded to 'genuine' granite or limestone ballast that was not electrically conductive.
There was a short story in the magazine some years about the Illinois Central which contained such an anecdote, I believe it focus on the period where Hunter Harrison took over and revolutionized IC, for better or worse. As I recall the IC mainline had historically had a lot of perishable freight traffic in iced or brine cooled reefers, and over the years quite a bit of 'coolant' had leaked out and accumulated in the grade. It also mentioned that the old IC signal system used relatively high voltage track circuits, and this combination meant that whenever it rained the ballast could become conductive and blocks would randomly drop and then clear again even if there were no trains in the area.
Corrections are welcomed if I'm recalling anything incorrectly here.
Greetings from Alberta
-an Articulate Malcontent
The above seems to indicate that a vary serious ballast cleaning and undercutting is a possible solution if signal system and crossing gate detection is compromised.
I believe one version of the 'conductive when wet' ballast story is in the 100-year volume of signals and safety that WABTEC published, in the discussion of code systems that used vane relays. Look for the phrase "bloop - bloop - bloop".
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