Section 238.731 - Brake system(a)General. Each railroad shall demonstrate through analysis and testing the maximum safe operating speed for its Tier III trainsets that results in no thermal damage to equipment or infrastructure during normal operation of the brake system.(b)Minimum performance requirement for brake system. Each Tier III trainset's brake system shall be capable of stopping the trainset from its maximum operating speed within the signal spacing existing on the track over which the trainset is operating under the worst-case adhesion conditions defined by the railroad, as approved by FRA.(c)Emergency brake system. A Tier III trainset shall be provided with an emergency brake application feature that produces an irretrievable stop. An emergency brake application shall be available at any time, and shall be initiated by either of the following:(1) An unintentional parting of the trainset; or(2) The train crew at locations within the trainset specified by the railroad, as approved by FRA.(d)Passenger brake alarm.(1) A means to initiate a passenger brake alarm shall be provided at two locations in each unit of a Tier III trainset that is over 45 feet in length. When a unit of the trainset is 45 feet or less in length, a means to initiate a passenger brake alarm need only be provided at one location in the unit. These locations shall be identified by the railroad as approved by FRA. The words "Passenger Brake Alarm" shall be legibly stenciled or marked on each device or on an adjacent badge plate.(2) All passenger brake alarms shall be installed so as to prevent accidental activation.(3) During departure from the boarding platform, activation of the passenger brake alarm shall result in an emergency brake application.(4) A passenger brake alarm activation that occurs after the trainset has safely cleared the boarding platform shall be acknowledged by the engineer within the time period specified by the railroad, as approved by FRA, for train operation to remain under the full control of the engineer. The method used to confirm that the trainset has safely cleared the boarding platform shall be defined by the railroad as approved by FRA.(5) If the engineer does not acknowledge the passenger brake alarm as specified in paragraph (d)(4) of this section, at a minimum, a retrievable full service brake application shall be automatically initiated until the trainset has stopped unless the engineer intervenes as described in paragraph (d)(6) of this section.(6) To retrieve the full service brake application described in paragraph (d)(5) of this section, the engineer must acknowledge the passenger brake alarm and activate appropriate controls to issue a command for brake application as specified by the railroad, as approved by FRA.(e)Degraded performance of blended brake system. The following requirements of this paragraph (e) apply to operation of Tier III trainsets with blended braking systems, to address degraded brake system performance: (1) Loss of power or failure of the dynamic or regenerative brake shall not result in exceeding the allowable stopping distance defined by the railroad as approved by FRA;(2) The available friction braking shall be adequate to stop the trainset safely under the operating conditions defined by the railroad, as approved by FRA;(3) The operational status of the trainset brake system shall be displayed for the engineer in the operating cab; and(4) The railroad shall demonstrate through analysis and testing the maximum speed for safely operating its Tier III trainsets using only the friction brake portion of the blended brake with no thermal damage to equipment or infrastructure. The analysis and testing shall also be used to determine the maximum safe operating speed for various percentages of operative friction brakes and shall be included in the railroad's ITM program.(f)Main reservoir system.(1) The main reservoirs in a Tier III trainset shall be designed and tested to meet the requirements of a recognized standard specified by the railroad as approved by FRA, such as the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code for Unfired Pressure Vessel Section VIII, Division I (ASME Code). The working pressure shall be 150 psig (10.3 bar) and the corresponding rated temperature shall be 150 °F (65 °C) unless otherwise defined by the railroad as approved by FRA. Reservoirs shall be certified based on their size and volume requirements.(2) Each welded steel main reservoir shall be drilled in accordance with the requirements of a recognized standard specified by the railroad as approved by FRA, such as paragraph UG-25(e) of Section VIII of the ASME Boiler and Pressure Vessel Code. With the drain opening located at the low point of the reservoir, one row of holes shall be drilled lengthwise on the reservoir on a line intersecting the drain opening and sloped to the drain opening.(3) A breach of a welded steel main reservoir at any of the drilled holes described in paragraph (f)(2) of this section shall be cause for the reservoir to be condemned and withdrawn from service. Any type of welded repair to a steel main reservoir is prohibited.(g)Aluminum main reservoirs.(1) Aluminum main reservoirs used in a Tier III trainset shall conform to the requirements of § 229.51 of this chapter.(2) Any type of welded repair to an aluminum main reservoir is prohibited.(h)Main reservoir tests. Prior to initial installation, each main reservoir shall be subjected to a pneumatic or hydrostatic pressure test based on the maximum working pressure defined in paragraph (f) or (g) of this section, as appropriate, unless otherwise established by the railroad's ITM program. Records of the test date, location, and pressure shall be maintained by the railroad for the life of the equipment. Periodic inspection requirements for main reservoirs shall be defined in the railroad's ITM program.(i)Brake gauges. All mechanical gauges and all devices providing electronic indication of air pressure that are used by the engineer to aid in the control or braking of a Tier III trainset shall be located so they may be conveniently read from the engineer's normal position during operation of the trainset.(j)Brake application/release.(1) Brake actuators shall be designed to provide brake pad and shoe clearance when the brakes are released.(2) The minimum brake cylinder pressure shall be established by the railroad, as approved by FRA, to provide adequate adjustment from minimum service to full service for proper train operation.(k)Foundation brake gear. The railroad shall specify requirements in its ITM program for the inspection, testing, and maintenance of the foundation brake gear.(l)Leakage.(1) If a Tier III trainset is equipped with a brake pipe, the leakage rates shall not exceed the limits defined in either paragraph (l)(2) of this section, or those defined in the Air Consumption Analysis included in the railroad ITM program, whichever is more restrictive. The method of inspection for main reservoir pipe leakage shall be prescribed in the railroad's ITM program.(2) Brake pipe leakage may not exceed 5 p.s.i. per minute; and with a full service application at maximum brake pipe pressure and with communication to the brake cylinders closed, the brakes shall remain applied for at least 5 minutes.(m)Slide protection and alarm.(1) A Tier III trainset shall be equipped with an adhesion control system designed to automatically adjust the braking force on each wheel to prevent sliding during braking.(2) A wheel-slide alarm that is visual or audible, or both, shall alert the engineer in the operating cab to wheel-slide conditions on any axle of the trainset.(3) The railroad shall specify operating restrictions for trainsets with slide protection devices for when they fail to prevent wheel slide within safety parameters preset by the railroad. Both the operating restrictions and safety parameters shall be approved by FRA.(n)Monitoring and diagnostics. Each Tier III trainset shall be equipped with a monitoring and diagnostic system that is designed to automatically assess the functionality of the brake system for the entire trainset. Details of the system operation and the method of communication of brake system functionality prior to the departure of the trainset and while en route shall be described in detail in the railroad's ITM program.(o)Train securement. Independent of the pneumatic brakes, Tier III equipment shall be equipped with a means of securing the equipment against unintentional movement when left standing and unmanned in such a manner that the brake system of the equipment cannot be readily controlled by a qualified person. The railroad shall develop the procedures used to secure the equipment and shall also demonstrate that those procedures effectively secure the equipment on all grade conditions identified by the railroad, as approved by FRA.(p)Rescue operation; brake system. A Tier III trainset's brake system shall be designed to allow a rescue vehicle or trainset to control its brakes when the trainset is disabled.