In addition to the "L" Canarsie. I think the "7" Flushing Line either already uses moving blocks or will soon.
But thus far nop part of the North American freigbht railroad systerm.
Lithonia Operator Hi greyhounds. Again, I appreciate your response on that. Now please help me out on something else. Your quote from the article made want to go back and see if the author expanded more on that, but I had forgotten. This is embarrassing, but I have scanned that article four times now, and can't find anything about the rail defect issue at all! Just can't find it. Senior brain fail, apparently. Where IS that? ?? I just turned 71, and occurrences like this are becoming more frequent. I either forget stuff, or "remember" stuff my wife can prove never happened!
Hi greyhounds. Again, I appreciate your response on that.
Now please help me out on something else. Your quote from the article made want to go back and see if the author expanded more on that, but I had forgotten.
This is embarrassing, but I have scanned that article four times now, and can't find anything about the rail defect issue at all! Just can't find it. Senior brain fail, apparently. Where IS that? ??
I just turned 71, and occurrences like this are becoming more frequent. I either forget stuff, or "remember" stuff my wife can prove never happened!
Mystery solved! I was talking about the Trains (paper) mag artticle, and you were talking about an online newswire article: https://trn.trains.com/news/news-wire/2021/02/09-bnsf-receives-patent-for-moving-block-system
And that online article must be where I myself got the idea about rail defects also.
According to Wikipedia, these are the only places in the world where moving blocks are currently in use"
Moving block is in use on several London Underground lines, including the Victoria line, Jubilee line, and the Northern line as well as the Docklands Light Railway.[2][3] New York City Subway's BMT Canarsie Line (L train), Tren Urbano (Puerto Rico),[4] the Singapore MRT's North South line, North East line, Circle line and Downtown line, and Vancouver's SkyTrain, also employ moving block signalling. It is also used by the Hong Kong MTR, on the West Rail line and the Ma On Shan line.[2]
Am I wrong, or is not BNSF simply using the old fixed-block technology with greate precision than before? Simply dividing the old two-mile blocks into five or ten shorter blocks? Don't have to use insulated joints, and transit systems have not used them in years. Use different AC frequencies for the adjacent (here short) blocks and the applicable filters and solid-state switching at each break-point. Boken rails are thus detected in the same classic manor, but the location is better determined.
Or is it a true moving block system that measures actual distance between trains?
I have my doubts.
Lithonia OperatorThis is embarrassing, but I have scanned that article four times now, and can't find anything about the rail defect issue at all! Just can't find it. Senior brain fail, apparently. Where IS that? ?? I just turned 71, and occurrences like this are becoming more frequent. I either forget stuff, or "remember" stuff my wife can prove never happened!
You don't have much age on me. I turned 70 in November 2020.
Anyway, I quoted the last sentence in the 9th paragraph. It's right after a one sentence paragraph.
Is the new signalling system that the NYC 7 subway/elevated line a moving block system?
greyhounds Lithonia Operator The article says that moving blocks will make detection of broken rails easier. Why would that be? What it actually says is: “In addition, by partitioning the physical track blocks into multiple virtual track blocks, broken rail can be detected within an occupied physical track block.” I'm a marketing guy, not an operating guy. But I'll take a stab at this. Corrections are more than welcome. Currently, once a train passes the fixed signal at the beginning of a block it has no protection against a rail break, or anything else, occurring in the block while it's in the block. If there is a pull appart due to cold weather there is no way to warn the train since it has already passed the signal. Same thing with a switch. If a switch is changed after a train has passed the signal there is no way to warn the train. It has already passed the guarding signal. With a moving block system the train is never past a signal. Since the block moves with the train anything happening ahead of the train can be communicated to the train. Granted, if the pull appart or switch allignment happens 200 feet ahead of the train this is not going to do much good. But if it's a mile or so ahead of the train effective action may well be possible.
Lithonia Operator The article says that moving blocks will make detection of broken rails easier. Why would that be?
What it actually says is: “In addition, by partitioning the physical track blocks into multiple virtual track blocks, broken rail can be detected within an occupied physical track block.”
I'm a marketing guy, not an operating guy. But I'll take a stab at this. Corrections are more than welcome.
Currently, once a train passes the fixed signal at the beginning of a block it has no protection against a rail break, or anything else, occurring in the block while it's in the block. If there is a pull appart due to cold weather there is no way to warn the train since it has already passed the signal. Same thing with a switch. If a switch is changed after a train has passed the signal there is no way to warn the train. It has already passed the guarding signal.
With a moving block system the train is never past a signal. Since the block moves with the train anything happening ahead of the train can be communicated to the train. Granted, if the pull appart or switch allignment happens 200 feet ahead of the train this is not going to do much good. But if it's a mile or so ahead of the train effective action may well be possible.
IIRC, Predictive signal circuits don't use joints, except possibly for the island circuits.
They don't work well under "rusty rail" conditions, but on lines as busy as we're generally talking about, they won't be a problem at all.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
BaltACDRemove the insulated joints and watch the crossing gates go down all across the track segment when a train occupies it.
Unless they do the PTC-controlled gates (Denver RTD ever get theirs figured out?).
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
rdamonWithout all those pesky insulated joints at the blocks they can use a 9V battery and a light bulb to test the entire system :)
Remove the insulated joints and watch the crossing gates go down all across the track segment when a train occupies it.
Never too old to have a happy childhood!
9v battery *AND* a light bulb?
Shareholders aren't going to stomach that.
Without all those pesky insulated joints at the blocks they can use a 9V battery and a light bulb to test the entire system :)
Lithonia OperatorThat's exactly what I am begining to wonder, after thinking about this.
If we are to believe some people - Neuropathic-osmosis via mental telepathy
That's exactly what I am begining to wonder, after thinking about this.
Broken rails are detected now when the electric current flowing through the rail is interupted by the break, causing a relay to drop out. How will PTB detect a break?
Mark Vinski
Lithonia OperatorBut it seems like an independent, different technology would have to be used for detecting flaws, misaligned switches, etc. So I think maybe Larry is right. Maybe the current track circuitry could be modified/enhanced to deal better solely with track-condition issues.
Sounds like cab signals ( a syytem that's been around 100 years+)
BaltACDWho thinks rails break on their own?
Most of the time the actual propagation of a break starts under traffic, but the actual failure -- the most obvious being severe cold tension breaks -- need not occur under a train. I think there is some incidence of bad welds, and some of the reported gauge-corner cracking damage became catastrophic with released shock in the beam of the rail, a bit like shattering tempered glass, not just at the point of impact damage.
The counterpart, sun kink, often doesn't need a train either, although it sure can get worse quickly as trains go over it. A combination of the two was the progressive kink on the ex-New Haven that was reported as steadily worsening by a couple of engineers and then produced either a derailment or sideswipe collision (I don't remember precisely which without checking) -- it was observed to get worse between trains as well as after each successive one.
Things that fall on rails, or that roll down roads or off bridges and hit rails, can cause damage too.
Who thinks rails break on their own?
They break when they have defects that the stress of a train passing over them progress the defect to the point of actual breakage.
On further reflection, I totally get how GPS can be used to create a virtual, moving envelope of protection. And, if it works correctly, would be good at preventing train-train collisions.
But it seems like an independent, different technology would have to be used for detecting flaws, misaligned switches, etc. So I think maybe Larry is right. Maybe the current track circuitry could be modified/enhanced to deal better solely with track-condition issues.
Broken rails not found by physical inspection in signalled territory are found by the disruption of continuity in the rail.
It could be that in removing the need to sense trains that technologies that could better sense a broken rail could be used, as they would not need to compete with train sensing methods.
In the fiber optic world, testers can see exactly where splices have been made.
Actually that makes no sense in the real world.
Train enters a track segment on a 'good' signal indication - train moves through the block and THE TRAIN breaks a rail underneath it as it passes. Subsequent trains that pass that formerly 'good' signal will now get a 'bad' signal.
My observation of the chain of events is based upon more than 20 years of first hand experience with the situations. Within the breadth of my territory, the first 'cold snap' of the Winter would generally generate between 6 and 12 broken rails or pulled apart rail joints over tha night. All were found 'AFTER' the passage of a train that had operated through the segment on 'good' signals.
You don't get 'good' signals into a track segment that has a broken rail or pulled apart rail joint. The vibration, impact or other stresses generated by the passage of a train is what brings about the ultimate failure.
Thanks, greyhounds. That makes sense. I very much appreciate the explanation.
That is indeed a great feature of moving blocks. I wonder how long it will be before we see a RR doing this. There will be an awful lot riding on the software. You can simulate things all day long, but at some point the railroad will have to try real-world tests. It's a little spooky. Once the GPS on my sailboat showed us as being in Portland (ME) harbor, when that was about 75 miles away. Apparently there was a magnetic disturbance where we were; another boat reported a similar anomaly. Another time, I created a waypoint in open water, and used it successfully to navigate. But the next time I was in the area, I wanted to use the waypoint, but couldn't find it; when I finally did, it was situated smack dab in the center of an island! Then, when I tried to move it or delete it, the GPS would not allow me to. So, although I have 198 other perfect waypoints, that one still sits on the island in Penobscot Bay. Point being, this stuff has glitches. Ask Boeing. Traditional lineside block signals have served well for a long time ...
Lithonia OperatorThe article says that moving blocks will make detection of broken rails easier. Why would that be?
The article says that moving blocks will make detection of broken rails easier.
Why would that be?
Well, now we've got this. Moving blocks might be closer than we realize.
BNSF receives patent for moving block system | Trains Magazine
jeffhergert The most far-fetched, most unlikely thing to happen for the foreseeable future. "Ultra reliable communications." They are going to have to start maintaining some of the simplest components better than they do. Jeff
The most far-fetched, most unlikely thing to happen for the foreseeable future. "Ultra reliable communications."
They are going to have to start maintaining some of the simplest components better than they do.
Jeff
Even face to face we sometimes have a failure to communicate.
Beverly (Cedar Rapids), where trains go to die. Mainly because most of the trains that need to work all show up at the same time. Even when they try to stagger call times at Boone to space trains.
Then a 10000 ft manifest picks up another 2000 ft solid block off the south side and another 2000 ft solid block off the north side. Might have to reposition engines to new DP configurations. Now you have a 14000 ft train that needs an initial terminal air test for the entire train. Better have a relief crew ready.
greyhounds OK, let’s presume that they eventually get this whole PTC/moving block thing working. There will be bugs and those bugs will need to be worked through. This happens with everything. While this is going on, many people will be complaining about “Change”. People don’t like two things; 1) Change and 2) The way things are now. So anyway, this whole moving block thing will require ultra-reliable communication between the lead train and the following train. If the lead train goes into emergency the following train needs to react immediately. So, if they get that worked out to 99.999% reliability, what can we do from there? Let’s talk about a set out at Cedar Rapids, IA. (My favorite “For Example” place.) Leave us just say that we’ve got a westbound out of Chicago for North Platte carrying a Cedar Rapids set out block. (OK, just to be clear, the word “Block” can have at least two meanings in railroading. As used above it means a section of track. As used in this paragraph forward it means a group of freight cars. Got that?) Current, and forever past, practice requires the entire train to stop. Then a “Ground Person” (gender neutral), or “Ground Persons” must manually uncouple the freight cars at the end of the block (group of cars). Leave the rest of the train sitting still (I hate that) and move forward past a switch. Then the switch must be changed so that a reverse movement will put the set-out block on a different track. Then the lead locomotives must reverse and shove the set-out block on to another track. Then the locomotives must be uncoupled by a ground person from the freight cars. Handbrakes must be set. Then the locomotives must move forward past the switch. The switch must again be changed so that the locomotives can back on to their train. A ground person must attend the recoupling and hook up the air hose. After the air brakes are found to be working properly the train may proceed on its journey to North Platte after spending a lot of time sitting still and blocking a track by not moving. Yetch! Now let’s do it with the “Power Stays with Block” concept introduced by Oltman. Add in the ultra-reliable communications. Also add “Helperlink” technology and software. So, the train is approaching Cedar Rapids from Chicago. There’s a DP unit toward the back of the train but in front of the Cedar Rapids block. It's got the Helperlink. (The Cedar Rapids set-out is on the rear of the train.) At a designated point, the Helperlink is cued remotely to separate the DP unit and block from the train. An EOT device on the preceding car immediately activates. A RC operator takes over, slows the set-out, a switch is thrown, and he/she brings the set-out on to its proper track. The rest of the train just keeps on rolling toward North Platte. It would save time and money as well as improve service to customers. A pick-up? Well I haven’t thought that through yet. Is this a fantasy? Oh, maybe. But with the communications tech we have today, and with what we will develop in the future, who knows. It could happen.
tree68 zugmann I've done moves where you pull into a yard, a yard crew (which PSR/some style management doesn't like) - grabs onto your rear end set out - a utility (again, PSR and certain managers hate these) then moves and rehangs the marker and launches you out on your way. So, how does this square with PTB?
zugmann I've done moves where you pull into a yard, a yard crew (which PSR/some style management doesn't like) - grabs onto your rear end set out - a utility (again, PSR and certain managers hate these) then moves and rehangs the marker and launches you out on your way.
So, how does this square with PTB?
Fine if PTB has that reality accounted for in its software.
For decades B&O and later CSX had a scheduled train totally based on rear end setoff. Train 396 which in later CSX days became 296, originated in Flint MI with autoparts for the GM Assembly plants in Baltimore and Wilmington. Train operated with a caboose as the rear Wilmington car that was ahead of all the Baltimore cars, with the required caboose on the rear. Train arrived Bayview Yard in Baltimore for a crew change and set off - Bayview yard crew was sent out on the other Main to make the cut behind the Wilmington caboose and the train started to pull picking up the Conductor & Flagman on the Wilmington caboose on the fly as it passed BA Tower. Arrival to departure was normally 10 minutes. After cabooses were removed from trains the Bayview yard crew would make the cut behind the last Wilmington car and rehang the EOT from the rear of the Baltimore's.
Today neither Wilmington nor Baltimore have GM Assembly plants.
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