Today’s Headlines

  • NYT: Cuomo Should Base His Congestion Pricing Plan on Move NY
  • So Far the Plan Is Just a Trial Balloon Cuomo Floated to the Times (Crain’s)
  • Signal Upgrades on the 7 Delayed Until 2018. Will the MTA Pick Up the Pace? (NYT)
  • Cuomo Plans a Low-Key Opening for His Big, Subsidized Highway Sprawl Bridge (D&C)
  • De Blasio Asks City Council to Back Him Up on an MTA Millionaires Tax (Politico)
  • Daneek Miller Dusts Off His Anti-Congestion Pricing Talking Points (Queens Press)
  • Hit-and-Run Driver Critically Injures Cyclist Lorenzo Anderson, 59, in Astoria (News)
  • Cab Driver Crashes Into Flatbed Truck on Cross Bronx Expressway and Dies (Post)
  • Driver Fleeing Traffic Stop Drags Cop 200 Feet (News)
  • Speeding Motorists Menace 72nd Ave in Forest Hills (QChron)
  • If You Ride the Bus, WNYC Wants to Hear From You

More headlines at Streetsblog USA

  • Vooch

    gov’t bus driver drags & kills citizen equals a1/2 mile $750 fine

    citizen drags gov’t employee 200 ft – what is likely punishment ?

  • Larry Littlefield

    The Flushing Line was supposed to be the second CBTC pilot, with things going much faster and easier after that. (Note the first two CBTC lines have no interlining).

    But given the price, the two-decade timeline, and the rapid advance of everything else EXCEPT rail transit, I wonder if the wise move isn’t to just junk it and start almost from scratch. I almost get the feeling that it a couple of years it will be possible to redo the entire system, twice (double redundancy), for the cost of either Flushing or Canarsie CBTC alone.

  • Fool

    MTA invented a “non-proprietary” two-way radio based communication based train control. The system utilizes active RFID chips installed on the track bed, which the train itself then reports its position through a radio connection. The reason for this “invention” was so that no cables had to be permanently installed. -Because cables would be stolen, a glorious argument against government bureaucracies.

    The real question is that since they are utilizing infrastructure as stupidly simple as active RFID, no power or communications data to be run to the unit, why are they taking so long to perform the installations?

    Another question: With such an ineffective labor force as the MTA, where the signal inspectors scanned printed copies of the safety barcodes rather than perform actual work, what happens in 5 to 10 years when the Active RFID runs out of battery power? Because you know the labor force is useless at maintaining infrastructure.

  • Nick Ober

    Why would the RFID tags on the rail bed need to be active? If the train rolling above has a powered interrogator, the rail bed tag should simply need to be passive with no battery onboard.

  • sbauman

    The rumor I heard regarding the delay in completing the Flushing Line’s CBTC is that resources were diverted to station rehabs. Somebody with more inside NYCT information will have to confirm this. My source had an interest in blaming CBTC implementation delays on something other than CBTC.

  • AMH

    Very interesting–my understanding was that installation was complete and testing is what’s taking so long. I can’t imagine using battery-powered wayside equipment–is that true?

  • sbauman

    The big question in CBTC is how the train knows its position. An open air system might be able to use GPS.

    That’s not possible in a tunnel. Dead reckoning is used. Count the number of wheel revolutions, multiply the wheel diameter by pi to get the position. Counting wheel revolutions is easy and accurate. However, the tolerance in wheel diameter leads to unacceptable systemic errors. The solution is to reset the position, when the expected error is still acceptable. Position beacons are distributed along the track. I believe the Canarsie Line initially used an optical sensor that proved unreliable. The Flushing Line implementation is using RFID tags.

    However, that’s not the communications part of CBTC. The train must communicate its position to the control system in a timely manner. The successful CBTC implementations used either inductive coupling or leaky transmission lines. This required required expensive maintenance, so they decided that radio communication would be used between the train and the control system. The MTA chose a proprietary radio communications system. This choice made the MTA’s installation much more expensive compared to other systems that used non-proprietary radio communications.

    It’s probably likely that most types of radio communications CBTC implementations will be banned because of security reasons. The radio communications does not have to be hacked; it just has to be made inoperable. This will cause trains to halt following trains in place to be sitting ducks for a terrorist. I suspect the FRA and the IEEE will re-examine their standards, after the first such attack. I hope, it’s not in NYC.

  • sbauman

    Why would the RFID tags on the rail bed need to be active?

    Communications reliability over a long distance. While passive RFID is contactless, it’s usually has to touch the RF interrogator.

  • Fool

    The tunnels are already lined with radiating cable within the 2m coupling mode range of the subscriber antennas, so it is very unlikely that the signal would could be easily jammed from someone on the platform (out of the coupling range of the radiating cable) or on the train (Faraday cage).

    CBTC modem side is utilizing the radiating cable in the tunnels, there is no such thing as a proprietary antenna.

    CBTC is not sexy brand new technology and pretty ancient in terms of communications engineering. But the MTA fucked up big time on not buying a proprietary commercial off the shelf equipment and insisting on wireless, active RFID beacons.

  • Fool

    Passive RFID does not have the range. Like RFID a transmitter on the train sends a signal that “activates” the return signal from the chip, but it needs additional power amplification for the range. Shelf life is typically 5 to 10 years on these things.

    As I alluded to earlier, I do not trust the MTA track and signal workers to maintain these things.

  • Jeffrey Baker

    You can interrogate passive RFIDs from across a huge material handling facility like a warehouse or container shipping facility. It should be no problem to interrogate them at a distance of < 1m.

  • Joe R.

    Same here. In fact, when the discussion of platform doors came up last year I was against the idea because I know the doors won’t be maintained. Only a matter of time before half the platform doors at a station don’t work. I don’t expect the batteries on the RFID tags will be changed regularly either. The only hope is that we’ll eventually have passive RFID capable of working in a rail environment.

  • Joe R.

    Remember this is the MTA we’re talking about. What is simple, quick, cheap, reliable, and routine elsewhere always becomes a monumental, expensive, lengthy, and failure-prone megaproject once the MTA gets its hands on it.

  • sbauman

    The purpose of the beacons is to correct dead reckoning systemic errors in position. Therefore, the distance from which an RFID beacon responds to an interrogation must be controlled. A response from 1 meter away, with a corresponding uncertainty, would not be useful because 1 centimeter accuracy is required.

  • qrt145

    Why is 1 cm accuracy required? I’m genuinely curious as I’m not an engineer.

  • sbauman

    Why is 1 cm accuracy required?

    The automatic train operation (ATO) spec for stopping in a station is 1/8 inch. If the train does not know it’s position to at least this accuracy and precision, such operation is not possible.

    The spec is this tight to accommodate fully automatic operation (ZPTO), like Paris Line 14, with platform doors. The train’s doors must line up with the doors on the platform. Think about the tolerance required for fully automatic elevator operation. There’s no discernible difference vertical difference between the elevator and building floors, when the elevator door opens.

  • qrt145

    Thank you, that makes sense. I didn’t know the system we were talking about was meant to support fully automated operation!