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					                           MINUTES OF MEETING
      IEEE GUIDE FOR THE CALUCLATION OF BRAKING DISTANCES FOR RAIL
              TRANSIT VEHICLES STANDARDS COMMITTEE (WG #25)

Meeting Date:          October 17th, 2005

Meeting Location:      SYSTRA Consulting Office
                       1601 Market Street, 17th Floor
                       Philadelphia, PA

Attendees:
        Jim Dietz                       Kamel Mokhtech
        John Ewing                      Dave Phelps
        Jim Hoelscher                   Jack Ronalter
        Geoff Hubbs                     Donald Sandala
        Paul Jamieson                   David Thurston
        John LaForce                    Tony Zakel

Attachments:           A.     Agenda for IEEE WG25 Braking Distance Standard Committee
                       B.     Safe Braking Distance Calculation Proposal
                       C.     Signaling and Capacity Through Computer Modeling (David
                              Thurston paper, February 26th 2004)

Conventions used in these minutes: Action items are shown in bold italics.

1.0     Agenda

        A detailed agenda was provided in advance of the meeting to aid the discussions. These
        minutes are modified from the agenda.

2.0     Housekeeping

2.1     Minutes of Previous Meeting

        As this is the first meeting of Working Group #25, there are no previous minutes.

2.3     Next Meeting

        The next meeting will be at Parsons Transportation Group offices in Baltimore, MD on
        December 12th at 9AM. The office is located in downtown Baltimore at 10 East
        Baltimore Street, Suite 801, Baltimore MD.
3.0   Committee Issues

3.1   Policies and Procedures

      A. Per the attachment, this Working Group is to develop a guide, not a standard, for the
         calculation of braking distances for rail transit vehicles. Consensus was reached that
         this included airport people movers, light rail, heavy rail, commuter rail and freight
         applications. The guide will be written so that different entities can develop braking
         models to suit their needs and infrastructure. It was noted that if the rail transit
         vehicle was traveling on a shared-usage track (i.e., typical commuter rail practice),
         then the guide should also address braking distances for both types of vehicles
         traveling on the shared track.

      B. It is anticipated that the guide will be developed within 1 year. Due to this schedule,
         it is envisioned that a Working Group meeting will be conducted every other month.

      C. It was noted that this Working Group is not a balloting group since this Group is
         development a guide, not a standard.

      D. Dave T. provided a brief presentation on IEEE rules for proprietary and anti-trust
         discussions at the Working Group. These rules will be presented at the start of every
         meeting.

3.2   Funding Status

      J. Dietz noted that at this time that it was not yet clear if this Working Group would be
      developing a guide for the IEEE, or ATPA, or a combination of both. This should be
      clarified at the next Working Group meeting.

4.    Standard Development Actions

4.1   Overview and Definitions

      A. It was noted that definitions from other Working Groups can be used for our Working
         Group so that definitions and abbreviations are consistent. Paul J. has maintained a
         compilation of definitions and abbreviations for all the IEEE Working Groups, and
         these are provided on the RSTVIC website
         (http://grouper.ieee.org/groups/railtransit/).

      B. The overview of the guide should define that the term “braking distance” takes into
         account all aspects of the vehicle and wayside upon entry into more restrictive
         territory, including propulsion, braking, vehicle overhang, safety factors, etc.

      C. Jim H. noted that braking models for Airport People Mover’s have already been
         developed as part of the IEEE standardization process. It was anticipated that there
         would be minimal difference between these braking models and the braking model
         developed by this Working Group. ACTION: Dave T. to investigate and determine
         the standard which outlines braking models for people movers.
        D. Dave P. volunteered to provide the IEEE standard style manual which the guide will
           follow when text is developed. The format/style for a guide is the same as for an
           IEEE standard.

        E. Definitions to be addressed in the guide:
            MAS – maximum authorized speed
            Buffer distance
            Preceding train overhang
            Brake assurance
            Reducing – this is a request for braking to reduce speed in advance of a curve, etc.
            Grades and Curvature.

        F. Consensus was reached that the guide should include typical examples of Braking
           Models in the body of the document, not in the annex.

 4.2    Braking Model Components

        A simplified illustration of the proposed Braking Model guide is provided for reference.

Speed


                                    E F G

                             D

            A       C



                                                                  H




                                                                                       I J




        B
                                                                                       Distance
        A. Maximum Entry Speed at Entry Point. The Maximum Entry Speed is also the
           Maximum Attainable Speed, which is the MAS plus a tolerance (usually 2-3 mph) to
           prevent a train from applying brakes instantaneously upon exceeding the MAS. It
   also should take into account equipment tolerances (i.e., wheel diameter, speed sensor
   error, etc.).

B. Entry Point. Entry Point is defined as the point where a train enters more restrictive
   territory. An Entry Point can be defined as a signal, impedance bond or insulated
   joint, or a transponder.

C. Reaction Time. This component of the Braking Model may consist of two parts:

      Equipment Reaction Times. The maximum reaction time of the carborne
       equipment to detect a more restrictive condition is typically the time allowed for
       the train to travel at the less-restrictive condition past the entry point in the
       absence of signal information. This time can also include the latency of the
       communications system transmitting signal information to the train from the
       wayside, and processing time on the wayside to determine the more-restrictive
       condition based upon train location. The Equipment Reaction Time also typically
       includes the time for the carborne equipment relay to drop due to the overspeed
       condition.
      Operator Reaction Time. This is the reaction time provided for action by the
       operator to suppress the overspeed condition, usually by either acknowledgement
       of the overspeed condition or through a manual application of brakes.

D. Runaway Acceleration. This is assumed to be the maximum acceleration rate
   available at the Maximum Entry Speed based upon the optimal vehicle performance
   characteristics. This component starts at the end of the Reaction Time. If Runaway
   Acceleration were to occur earlier, then the Braking Model would begin at the less-
   restrictive Maximum Entry Speed from territory prior to the Entry Point. Thus, the
   worst-case occurs when Runaway Acceleration occurs at the conclusion of the
   Reaction Time. Runaway Acceleration is typically included in Braking Models
   which feature ATO and microprocessor-based propulsion control logic. An
   interrelated failure analysis may also be performed. This component of the Model is
   grade compensated.

E. Jerk-Rate Limiting (Propulsion Removal). This component of the Braking Model
   involves the removal of propulsion simultaneously with the application of brakes.
   From a worst-case perspective, this is typically assumed to be half the acceleration
   rate of the vehicle at the train speed achieved at the end of the Runaway Acceleration
   period. This component should be verified by test, and defined in the vehicle
   technical specifications.

F. Dead Time. This component is after removal of propulsion, and prior to a 10%
   application of the braking system after command by the carborne signal equipment.
   The train is typically assumed to be in coast during this time. Again, this component
   should be verified by test, and defined in the vehicle technical specifications.

G. Brake Build-Up. Brake Build-Up is the time for the train to “build-up” to the Braking
   Rate of a train from 10% (i.e., this is not the time to “build-up” to the full
   performance braking characteristic of the train). The train is typically assumed to
          have achieved half the deceleration rate of the Braking Rate during this period.
          Again, this component should be verified by test, and defined in the vehicle technical
          specifications.

       H. Braking Rate. The Braking Rate is a de-rated deceleration rate defined by a railroad
          or transit authority, and can either be a service brake or emergency brake application
          based upon the railroad or authority. It is based upon the application of friction
          brakes only, and is typically applied through fail-safe or safety-critical circuits. In
          some instances, allowance is provided here for brake assurance.

       I. Safety Factor. The Safety Factor is typically used to capture a range of issues that
          may not be addressed in other components of the Braking Model. These include the
          following:

             Adhesion levels
             The percentage of failed brakes on a train, both the percentage of brakes on a train
              in which the train can continue service and then additional brakes that may fail
              upon brake application due to the more restrictive condition at the Entry Point
             Operating Rules and Procedures
             Equipment tolerances (vehicle braking systems, etc.)
             Slip/slide systems
             Load weigh failures
             Magnitude of the Braking Rate used.

       J. Vehicle Overhang. This is the distance between the front coupler face of a train and
          the device which is used to detect the more-restrictive condition. This can be an
          antenna on the lead truck, a magnetic transponder, etc.

4.3    Sub-Committee Assignments

The following actions were taken by the various Working Group individuals to be completed
prior to the next meeting:

       A. Tony Z. and Don S. to develop preliminary language for the Braking Model
          components A through C defined in 4.2 above.

       B. John E., Paul J. and Jack R. to develop preliminary language for Braking Model
          components D through G defined in 4.2 above.

       C. Dave T. to develop preliminary language for Braking Model components H, I and J
          defined in 4.2 above.

       D. Jim H. to submit to Dave T. an electronic version of P679.1 dated May 1982 of an
          IEEE Proposed Recommended Practice for the Determination of Safe Braking
          Distance in Fixed Guideway Land Transportation Systems (this Practice was never
          published).

       E. Dave P. to provide the electronic template of an IEEE standard.

				
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