49 C.F.R. § 218.5
Absolute block means a block in which no train is permitted to enter while it is occupied by another train.
Associate Administrator for Safety means the Associate Administrator for Railroad Safety and Chief Safety Officer of the Federal Railroad Administration or that person's delegate as designated in writing.
Blue signal means a clearly distinguishable blue flag or blue light by day and a blue light at night. When attached to the operating controls of a locomotive, it need not be lighted if the inside of the cab area of the locomotive is sufficiently lighted so as to make the blue signal clearly distinguishable.
Camp car means any on-track vehicle, including outfit, camp, or bunk cars or modular homes mounted on flat cars used to house rail employees. It does not include wreck trains.
Car shop repair track area means one or more tracks within an area in which the testing, servicing, repair, inspection, or rebuilding of railroad rolling equipment is under the exclusive control of mechanical department personnel.
Controlling locomotive means a locomotive arranged as having the only controls over all electrical, mechanical and pneumatic functions for one or more locomotives, including controls transmitted by radio signals if so equipped. It does not include two or more locomotives coupled in multiple which can be moved from more than one set of locomotive controls.
Designated crew member means an individual designated under the railroad's operating rules as the point of contact between a train or yard crew and a utility employee working with that crew.
Effective locking device when used in relation to a manually operated switch or a derail means one which is:
Flagman's signals means a red flag by day and a white light at night, and fusees as prescribed in the railroad's operating rules.
FTA means the Federal Transit Administration.
Group of workers means two or more workers of the same or different crafts assigned to work together as a unit under a common authority and who are in communication with each other while the work is being done.
Hazard means an existing or potential condition that could lead to an unplanned event or series of events that can result in an accident or incident (i.e., mishap); injury, illness, or death; damage to or loss of a system, equipment, or property; or damage to the environment.
Helper service train operation means the train is a locomotive or group of locomotives being used to assist another train that has incurred mechanical failure or lacks sufficient tractive force necessary to traverse a particular section of track due to train tonnage and the grade of the terrain.
Interlocking limits means the tracks between the opposing home signals of an interlocking.
Lite locomotive train operation means the train is a locomotive or a consist of locomotives not attached to any piece of equipment or attached only to a caboose.
Locomotive means, except for purposes of subpart F of this part, a self-propelled unit of equipment designed for moving other railroad rolling equipment in revenue service including a self-propelled unit designed to carry freight or passenger traffic, or both, and may consist of one or more units operated from a single control.
Locomotive, MU means rail rolling equipment self-propelled by any power source and intended to provide transportation for members of the general public.
Locomotive servicing track area means one or more tracks, within an area in which the testing, servicing, repair, inspection, or rebuilding of locomotives is under the exclusive control of mechanical department personnel.
Main track means a track, other than an auxiliary track, extending through yards or between stations, upon which trains are operated by timetable or train order or both, or the use of which is governed by a signal system.
Mishap means an event or condition or series of events or conditions resulting in an accident or incident.
Rolling equipment includes locomotives, railroad cars, and one or more locomotives coupled to one or more cars.
One-person train crew means either:
One-person train crewmember means, in the context of a one-person train crew operation, the single assigned person who is performing the duty of the locomotive engineer and is traveling in the operating cab of the controlling locomotive when the train is moving.
Risk means the combination of the expected probability (or frequency of occurrence) and the consequence (or severity) of a hazard.
Risk assessment means the process of determining, either quantitatively or qualitatively, or both, the level of risk associated with train operations with a one-person train crew, compared to operations with a two-person (or larger) crew, under all operating conditions.
Switch providing access means a switch which if traversed by rolling equipment could permit that rolling equipment to couple to the equipment being protected.
Switching service or switching operation means classifying rail cars according to commodity or destination; assembling of cars for train movements; changing the position of cars for purposes of loading, unloading, or weighing; placing locomotives and cars for repair or storage; or moving of rail equipment in connection with work service that does not constitute a train movement.
Tourist train operation means a tourist, scenic, historic, or excursion train operation.
Tourist train operation that is not part of the general railroad system of transportation means a tourist, scenic, historic, or excursion train operation conducted only on track used exclusively for that purpose (i.e., there is no freight, intercity passenger, or commuter passenger railroad operation on the track).
Trailing tons means the sum of the gross weights-expressed in tons-of the cars and the locomotives in a train that are not providing propelling power to the train.
Train means one or more locomotives coupled with or without cars, except during switching service.
Train or yard crew means one or more railroad employees assigned a controlling locomotive, under the charge and control of one crew member; called to perform service covered by Section 2 of the Hours of Service Act; involved with the train or yard movement of railroad rolling equipment they are to work with as an operating crew; reporting and working together as a unit that remains in close contact if more than one employee; and subject to the railroad operating rules and program of operational tests and inspections required in §§217.9 and 217.11 of this chapter.
Unit freight train means a freight train composed of cars carrying a single type of commodity.
Utility employee means a railroad employee assigned to and functioning as a temporary member of a train or yard crew whose primary function is to assist the train or yard crew in the assembly, disassembly or classification of rail cars, or operation of trains (subject to the conditions set forth in §218.22 of this chapter).
Worker means any railroad employee assigned to inspect, test, repair, or service railroad rolling equipment, or their components, including brake systems. Members of train and yard crews are excluded except when assigned such work on railroad rolling equipment that is not part of the train or yard movement they have been called to operate (or been assigned to as "utility employees"). Utility employees assigned to and functioning as temporary members of a specific train or yard crew (subject to the conditions set forth in §218.22 of this chapter), are excluded only when so assigned and functioning.
Note: Servicing does not include supplying cabooses, locomotives, or passenger cars with items such as ice, drinking water, tools, sanitary supplies, stationery, or flagging equipment.
Testing does not include (i) visual observations made by an employee positioned on or alongside a caboose, locomotive, or passenger car; or (ii) marker inspections made in accordance with the provisions of §221.16(b) of this chapter.
49 C.F.R. §218.5