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
That's exactly what I am begining to wonder, after thinking about this.
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
Never too old to have a happy childhood!
Without all those pesky insulated joints at the blocks they can use a 9V battery and a light bulb to test the entire system :)
rdamonWithout all those pesky insulated joints at the blocks they can use a 9V battery and a light bulb to test the entire system :)
9v battery *AND* a light bulb?
Shareholders aren't going to stomach that.
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
Remove the insulated joints and watch the crossing gates go down all across the track segment when a train occupies 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?).
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...
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.
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!
Is the new signalling system that the NYC 7 subway/elevated line a moving block system?
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.
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.
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]
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!
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.
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.
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