49 C.F.R. § 299.5
Definitions.
Cite as 49 C.F.R. § 299.5 (2026)
As used in this part—
Absolute block
means a block of track circuits in which no trainset is permitted to enter while occupied by another trainset.
Adjusting/de-stressing
means the procedure by which a rail's neutral temperature is readjusted to the desired value. It typically consists of cutting the rail and removing rail anchoring devices, which provides for the necessary expansion and contraction, and then re-assembling the track.
Administrator
means the Administrator of the FRA or the Administrator's delegate.
Associate Administrator
means FRA's Associate Administrator for Safety and Chief Safety Officer, or that person's delegate.
Automatic train control (ATC)
means the signaling system, composed of ground and on-board equipment. The on-board equipment continually receives a signal from the ground equipment. ATC on-board equipment controls the trainset speed to prevent train-to-train collisions and overspeed derailments.
ATC cut-out mode
means the mode of ATC on-board equipment used for emergency operations to disable the ATC on-board equipment on the trainset.
ATC main line mode
means the mode of ATC on-board equipment which controls trainset speed on mainlines.
ATC overrun protection
means an overlay of the ATC shunting mode to prevent overrun at the end of a track.
ATC shunting mode
means the mode of ATC on-board equipment which restricts the trainsets maximum speed to 30 km/h (19 mph).
Brake, air
means a combination of devices operated by compressed air, arranged in a system and controlled electrically or pneumatically, by means of which the motion of a train or trainset is retarded or arrested.
Brake, disc
means a retardation system used on the passenger trainsets that utilizes flat discs as the braking surface.
Brake, electric
means a trainset braking system in which the kinetic energy of a moving trainset is used to generate electric current at the traction motors, which is then returned into the catenary system.
Brake, emergency application
means a brake application initiated by a de-energized brake command and is retrievable when there is no malfunction that initiates an automatic emergency brake application. An emergency brake application can be initiated by the driver or automatically by ATC. An emergency brake application, as defined here, is equivalent to a full-service brake application in the U.S.
Brake, urgent application
means an irretrievable brake application designed to minimize the braking distance. An urgent brake application, as defined here, is the equivalent of an emergency brake application in the U.S.
Bogie
means an assembly that supports the weight of the carbody and which incorporates the suspension, wheels and axles, traction motors and friction brake components. Each unit of a trainset is equipped with two bogies. In the U.S., a bogie is commonly referred to as a truck.
Broken rail
means a partial or complete separation of an otherwise continuous section of running rail, excluding rail joints, expansion joints, and insulated joints.
Buckling incident/buckling rail
means the formation of a lateral misalignment caused by high longitudinal compressive forces in a rail sufficient in magnitude to exceed the track geometry alignment safety limits defined in § 299.311.
Buckling-prone condition
means a track condition that can result in the track being laterally displaced due to high compressive forces caused by critical rail temperature combined with insufficient track strength and/or train dynamics.
Cab
means the compartment or space within a trainset that is designed to be occupied by a driver and contain an operating console for exercising control over the trainset.
Cab car
means a rail vehicle at the leading or trailing end, or both, of a trainset which has a driver's cab and is intended to carry passengers, baggage, or mail. A cab car may or may not have propelling motors.
Cab end structure
means the main support projecting upward from the underframe at the cab end of a trainset.
Cab signal
means a signal located in the driver's compartment or cab, indicating a condition affecting the movement of a trainset.
Calendar day
means a time period running from one midnight to the next midnight on a given date.
Cant deficiency
means the additional height, which if added to the outer rail in a curve, at the designated vehicle speed, would provide a single resultant force, due to the combined effects of weight and centrifugal force on the vehicle, having a direction perpendicular to the plane of the track.
Continuous welded rail (CWR)
means rail that has been welded together into lengths exceeding 122 m (400 feet). Rail installed as CWR remains CWR, regardless of whether a joint is installed into the rail at a later time.
Consist, fixed
means a semi-permanently coupled trainset that is arranged with each unit in a specific location and orientation within the trainset.
Core system, high-speed
means the safety-critical systems, sub-systems, and procedures required for a high-speed system operation that assures a safe operation as required within this part.
Crewmember
means a railroad employee called to perform service covered by 49 U.S.C. 21103.
Critical buckling stress
means the minimum stress necessary to initiate buckling of a structural member.
Desired rail installation temperature range
means the rail temperature range in a specific geographical area, at which forces in CWR installed in that temperature range should not cause a track buckle in extreme heat, or a pull-apart during extreme cold weather.
Disturbed track
means the disturbance of the roadbed or ballast section, as a result of track maintenance or any other event, which reduces the lateral or longitudinal resistance of the track, or both.
Driver
means any person who controls the movement of a trainset(s) from the cab, and is required to be certified under 49 CFR part 240. A driver, as used in this part, is equivalent to a locomotive engineer.
Employee or railroad employee
means an individual who is engaged or compensated by the railroad or by a contractor to the railroad to perform any of the duties defined in this part.
Event recorder
means a device, designed to resist tampering, that monitors and records data, as detailed in §§ 299.439 and 236.1005(d) of this chapter, over the most recent 48 hours of operation of the trainset.
Event recorder memory module
means that portion of an event recorder used to retain the recorded data as described in §§ 299.439(c) and 299.449(a) through (c).
Expansion joint
means a piece of special trackwork designed to absorb heat-induced expansion and contraction of the rails.
General control center
means the location where the general control center staff work.
General control center staff
means qualified individuals located in the general control center who are responsible for the safe operation of the railroad's high-speed passenger rail system. The duties of individuals who work at the general control center include: Trainset movement control, crew logistic management, signaling, passenger services, rolling stock logistic management, and right-of-way maintenance management.
Glazing, end-facing
means any exterior glazing installed in a trainset cab located where a line perpendicular to the exterior surface glazing material makes horizontal angle of 50 degrees or less with the longitudinal center line of the rail vehicle in which the panel is installed. A glazing panel that curves so as to meet the definition for both side-facing and end-facing glazing is end-facing glazing.
Glazing, exterior
means a glazing panel that is an integral part of the exterior skin of a rail vehicle with a surface exposed to the outside environment.
Glazing, side-facing
means any glazing located where a line perpendicular to the exterior surface of the panel makes an angle of more than 50 degrees with the longitudinal center line of the rail vehicle in which the panel is installed.
High voltage
means an electrical potential of more than 150 volts.
Image recording device
means a device that records images, as described in § 299.449.
Image recording system
means a system of electronic devices capable of recording images as described in § 299.449, and any components that convert those images into electronic data transmitted to, and stored on, a certified crashworthy memory module as described in appendix A to this part.
In passenger service/in revenue service
means a trainset that is carrying, or available to carry, passengers. Passengers need not have paid a fare in order for the trainset to be considered in passenger or in revenue service.
In service
means, when used in connection with a trainset, a trainset subject to this part that is in revenue service, unless the equipment—
(1) Is being handled in accordance with § 299.447, as applicable;
(2) Is in a repair shop or on a repair track;
(3) Is on a storage track and is not carrying passengers; or,
(4) Is parked at a station location and has been properly secured in accordance with §§ 299.409(n) and 299.431(d).
Insulated joint, glued
means a rail joint located at the end of a track circuit designed to insulate electrical current from the signal system in the rail.
Interior fitting
means any component in the passenger compartment which is mounted to the floor, ceiling, sidewalls, or end walls and projects into the passenger compartment more than 25 mm (1 in.) from the surface or surfaces to which it is mounted. Interior fittings do not include side and end walls, floors, door pockets, or ceiling lining materials, for example.
Intermediate car
means a passenger car or unit of a trainset located between cab cars which may or may not have propelling motors.
L/V ratio
means the ratio of the lateral force that any wheel exerts on an individual rail to the vertical force exerted by the same wheel on the rail.
Lateral
means the horizontal direction perpendicular to the direction of travel.
Locomotive
means a piece of on-track rail equipment, other than hi-rail, specialized maintenance, or other similar equipment, which may consist of one or more units operated from a single control stand with one or more propelling motors designed for moving other passenger equipment; with one or more propelling motors designed to transport freight or passenger traffic, or both; or without propelling motors but with one or more control stands.
Longitudinal
means in a direction parallel to the direction of travel of a rail vehicle.
Marking/delineator
means a visible notice, sign, symbol, line or trace.
N700
means the N700 series trainset that is based on trainsets currently in, or future variants operated on, JRC's Tokaido Shinkansen system, or any unit thereof.
Occupied volume
means the volume of a passenger car or a unit in a trainset where passengers or crewmembers are normally located during service operation, such as the cab and passenger seating areas. The entire width of a vehicle's end compartment that contains a control stand is an occupied volume. A vestibule is typically not considered occupied.
On-board attendant
means a qualified individual on a trainset that is responsible for coordination with a station platform attendant to assure safety during passenger boarding and alighting within a station. An on-board attendant, as used in this part, is equivalent to a passenger conductor.
Override
means to climb over the normal coupling or side buffers and linking mechanism and impact the end of the adjoining rail vehicle or unit above the underframe.
Overrun protection coil
means track circuit cables placed short of turnouts, or crossovers within stations and trainset maintenance facilities to prevent unauthorized route access.
Passenger car
means a unit of a trainset intended to provide transportation for members of the general public. A cab car and an intermediate car are considered passenger cars.
Passenger compartment
means an area of a passenger car that consists of a seating area and any vestibule that is connected to the seating area by an open passageway.
Passenger equipment
means the N700 series trainset that is based on trainsets currently in, or future variants operated on, JRC's Tokaido Shinkansen system, or any unit thereof.
Permanent deformation
means the undergoing of a permanent change in shape of a structural member of a rail vehicle.
PTC
means positive train control as further described in § 299.201.
Qualified individual
means a person that has successfully completed all instruction, training, and examination programs required by both the employer and this part, and that the person, therefore, may reasonably be expected to perform his or her duties proficiently in compliance with all Federal railroad safety laws, regulations, and orders.
Rail neutral temperature
is the temperature at which the rail is neither in compression nor tension.
Rail temperature
means the temperature of the rail, measured with a rail thermometer.
Rail vehicle
means railroad rolling stock, including, but not limited to, passenger and maintenance vehicles.
Railroad equipment
means all trains, trainsets, rail cars, locomotives, and on-track maintenance vehicles owned or used by the railroad.
Railroad, the
means the company, also known as the Texas Central Railroad, LLC, which is the entity that will operate and maintain the high-speed rail system initially connecting Dallas to Houston, Texas, and is responsible for compliance with all aspects of this rule.
Repair point
means a location designated by the railroad where repairs of the type necessary occur on a regular basis. A repair point has, or should have, the facilities, tools, and personnel qualified to make the necessary repairs. A repair point need not be staffed continuously.
Representative car/area
means a car/area that shares the relevant characteristics as the car(s)/area(s) it represents (
i.e.,
same signage/marking layout, and charging light system for passive systems or light fixtures and power system for electrically powered systems).
Rollover strength
means the strength provided to protect the structural integrity of a rail vehicle in the event the vehicle leaves the track and impacts the ground on its side or roof.
Safety appliance
means an appliance, required under 49 U.S.C. ch. 203, excluding power brakes. The term includes automatic couplers, handbrakes, crew steps, handholds, handrails, or ladder treads made of steel or a material of equal or greater mechanical strength used by the traveling public or railroad employees that provides a means for safe coupling, uncoupling, or ascending or descending passenger equipment.
Safety-critical
means a component, system, software, or task that, if not available, defective, not functioning, not functioning correctly, not performed, or not performed correctly, increases the risk of damage to railroad equipment or injury to a passenger, railroad employee, or other person.
Search, valid
means a continuous inspection for internal rail defects where the equipment performs as intended and equipment responses are interpreted by a qualified individual as defined in subpart C.
Semi-permanently coupled
means coupled by means of a drawbar or other coupling mechanism that requires tools to perform the coupling or uncoupling operation. Coupling and uncoupling of each semi-permanently coupled unit in a trainset can be performed safely only while at a trainset maintenance facility where personnel can safely get under a unit or between units, or other location under the protections of subpart B of part 218 of this chapter.
Side sill
means that portion of the underframe or side at the bottom of the rail vehicle side wall.
Shinkansen, Tokaido
means the high-speed rail system operated by the Central Japan Railway Company between Tokyo and Shin-Osaka, Japan, that is fully dedicated and grade separated.
Slab track
means railroad track structure in which the rails are attached to and supported by a bed or slab, usually of concrete (or asphalt), which acts to transfer the load and provide track stability.
Spall, glazing
means small pieces of glazing that fly off the back surface of the glazing when an object strikes the front surface.
Speed, maximum approved
means the maximum trainset speed approved by FRA based upon the qualification tests conducted under § 299.609(g).
Speed, maximum authorized
means the speed at which trainsets are permitted to travel safely, as determined by all operating conditions and signal indications.
Speed, maximum safe operating
means the highest speed at which trainset braking may occur without thermal damage to the discs.
Station platform attendant
means a qualified individual positioned on the station platform in close proximity to the train protection switches while a trainset is approaching and departing a station, and is responsible for coordination with an on-board attendant to assure safety during passenger boarding and alighting within a station.
Superelevation
means the actual elevation of the outside rail above the inside rail.
Sweeper vehicle
means a rail vehicle whose function is to detect obstacles within the static construction gauge prior to the start of daily revenue service.
Tight track
means CWR which is in a considerable amount of compression.
Track acceleration measurement system (TAMS)
means an on-track, vehicle-borne technology used to measure lateral and vertical carbody accelerations.
Track geometry measurement system (TGMS)
means an on-track, vehicle-borne technology used to measure track surface, twist, crosslevel, alignment, and gauge.
Track lateral resistance
means the resistance provided to the rail/crosstie structure against lateral displacement.
Track longitudinal resistance
means the resistance provided by the rail anchors/rail fasteners and the ballast section to the rail/crosstie structure against longitudinal displacement.
Track, non-ballasted
means a track structure not supported by ballast in which the rails are directly supported by concrete or steel structures. Non-ballasted track can include slab track and track structures where the rails are directly fixed to steel bridges or to servicing pits within trainset maintenance facilities.
Train
means a trainset, or locomotive or locomotive units coupled with or without cars.
Train-induced forces
means the vertical, longitudinal, and lateral dynamic forces which are generated during train movement and which can contribute to the buckling potential of the rail.
Train protection switch
means a safety device located on station platforms and on safe walkways along the right-of-way. The train protection switch is tied directly into the ATC system and is used in the event that trainsets in the immediate area must be stopped.
Trainset
means a passenger train including the cab cars and intermediate cars that are semi-permanently coupled to operate as a single consist. The individual units of a trainset are uncoupled only for emergencies or maintenance conducted in repair facilities.
Trainset maintenance facility
means a location equipped with the special tools, equipment, and qualified individuals capable of conducting pre-service inspections and regular inspections on the trainsets in accordance with the railroad's inspection, testing, and maintenance program. Trainset maintenance facilities are also considered repair points.
Transponder
means a wayside component of the ATC system used to provide trainset position correction on the mainline or to provide an overlay of overrun protection within a trainset maintenance facility.
Underframe
means the lower horizontal support structure of a rail vehicle.
Unit, trainset
means a cab car or intermediate car of a trainset.
Vestibule
means an area of a passenger car that normally does not contain seating, is located adjacent to a side exit door, and is used in passing from a seating area to a side exit door.
Yard
means a system of tracks within defined limits and outside of the territory controlled by signals, which can be used for the making up of non-passenger trains or the storing of maintenance-of-way equipment.
Yield strength
means the ability of a structural member to resist a change in length caused by an applied load. Exceeding the yield strength will cause permanent deformation of the member.
[85 FR 69731, Nov. 3, 2020, as amended at 88 FR 70764, Oct. 12, 2023]
- Cross-references to the US Code
- 49:21103.
- Cross-references to the CFR
- 299.201.299.311.299.409299.439299.447299.449299.449.299.609