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Environmental Glossary

Abandonment: The discontinuance of service on a rail line segment, with no intention of resuming that service.

Active warning devices: Traffic control devices that give positive notice to highway users of the approach or presence of a train. These devices may include a flashing red light signal (a device which, when activated, displays red lights flashing alternately), a bell (a device which, when activated, provides an audible warning, usually used with a flashing red light signal), automatic gates (a mechanism added to flashing red light signals to provide a cantilevered arm that can lower across the lanes of the roadway equipped with flashing red light signals and extending over one or more lanes of traffic).

Adverse environmental impact: A negative effect, resulting from the implementation of a proposed action, that serves to degrade or diminish an aspect of human or natural resources.

Advisory Council on Historic Preservation (ACHP) : An independent Federal agency charged with advising the President and Congress on historic preservation matters and administering the provisions of Section 106 of the National Historic Preservation Act.

Applicants: Any person or entity seeking Board action whether by application, petition, Notice of Exemption, or any other means that initiates a formal Board proceeding.

Application: A formal filing with the Board related to certain railroad transactions such as railroad mergers, acquisitions, constructions, or abandonments. Applications may be either Primary applications or Inconsistent and Responsive (IR) Applications. See Primary Application and Inconsistent and Responsive (IR) Application.

Attainment area: An area that EPA has classified as complying with the National Ambient Air Quality Standards specified under the Clean Air Act.

Bad order cars: Rail cars that fail routine inspections. Bad order support tracks: Tracks used to store bad order cars until they can be repaired.

Ballast: The portion of the track bed that lies below the railroad ties and consists of crushed stone or other material.

Best Management Practice (BMP): Technique that various parties (e.g., the construction industry) use to minimize or avoid adverse impacts to the environment. The Board may designate these techniques as mitigation measures.

Block: (1) A defined length of track, with defined limits, on which operators govern train movements. (2) A group of freight cars handled as one unit for a portion or all of their journey from origin to destination.

Block swapping: The process of moving a group of rail cars with a common destination (called Ablocks) from one train to another.

Blocking: The process of aggregating freight cars onto blocks.

Board: The Surface Transportation Board.

Bulletins: Documents addressed to train crew and other operating employees specifying temporary or local operating rules and restrictions.

Census block group: The smallest geographic unit for which the U.S. Census provides information on racial background, ethnic heritage, and household income.

Clean Air Act (Clean Air Act Amendments): The Clean Air Act of 1970 and the subsequent amendments, including the Clean Air Act Amendments of 1990 (42 U.S.C. Act Amendments): The Clean Air Act of 1970 and the subsequent amendments, including the Clean Air Act Amendments of 1990 (42 U.S.C. Sections 7401-7671g); the primary Federal law that protects the nation’s air resources. This act establishes a comprehensive set of standards, planning processes, and requirements to address air pollution problems and reduce emissions from major sources of pollutants.

Clean Water Act: The Federal Water Pollution Control Act Amendment of 1972 (33 U.S.C. § 1251 et seq.) is the primary Federal law that protects the nation’s waters, including lakes, rivers, aquifers, and coastal areas. The act provides a comprehensive framework of standards, technical tools, and financial assistance to address the many causes of pollution and poor water quality, including municipal and industrial wastewater discharges, polluted runoff from urban and rural areas, and habitat destruction. Specifically, the Clean Water Act provides for the following: Requires major industries to meet performance standards to ensure pollution control. Charges state and tribes with setting specific water quality standards appropriate for their water and developing pollution control programs to meet them. Protects valuable wetlands and other aquatic habitats through a permitting process that conducts land development activities and other activities in an environmentally sound manner.

Common corridor: An area in which passengers and freight rail lines run on adjacent parallel lines.

Comprehensive Environmental Response Compensation, and and Liability Act of 1980 (42 U.S.C.  Section 9601-9675; P.L. 96-510); Liability Act (CERCLA): The Comprehensive Environmental Response, Compensation, the Federal act that provides EPA with authority to clean up inactive hazardous waste sites and distribute the cleanup costs among the parties who generated and/or handled the hazardous substances at these sites.

Comprehensive Environmental Response, Compensation, and Liability Information Environmental Response, Compensation, and Liability Information System (CERCLIS: Federal database containing information on potential hazardous waste sites that states, municipalities, private companies, and private persons have reported to the EPA, pursuant to Section 103 of the Comprehensive Environmental Response, Compensation, and Liability Act. This database contains sites that are either currently on, or proposed for inclusion on, the National Priorities List (NPL) and sites that are in the screening and assessment phase for possible inclusion on the NPL.

Condition: A provision that the Board imposes as part of any decision that requires action by one or more of the Applicants.

Control boxes: Structures at highway/rail at-grade crossings that house the electronics and the apparatus that control the warning devices at the crossing. Council on Environmental Quality (CEQ): Federal agency responsible for developing regulation and guidance for agencies implementing the National Environmental Policy Act.

Crew caller: Term applied to a railroad employee who is responsible for notifying train crews when and where to report for duty.

Crew calling: Process of notifying train crew members when and where their next tour-of-duty will start. Labor agreements commonly specify that railroads call train crews a minimum of 2 hours before crew members are required to begin their tour-of-duty. Criteria of significance: The criteria which the Section of Environmental Analysis has developed to determine whether a potential adverse environmental effect is significant and may warrant mitigation.

Critical habitat: The specific site within the geographical area occupied by threatened or endangered species that includes the physical or biological features essential to the conservation of the species. These areas may require special management considerations or protection. These areas include specific sites outside the geographical areas occupied by the species at the time of the listing that are essential for the conservation of the species.

Cultural resources: Any prehistoric or historic district, site, building, structure, or object that warrants consideration for inclusion in the National Register of Historic Places. A cultural resource that is listed in or is eligible for listing in the National Register of Historic Places is considered a historic property (or a significant cultural resource). The term generally applies to any railroad owned resource more than 50 years old.

Cumulative effects: Impact on the environment which results from the incremental impact of the proposed action when added to other past, present, and reasonably foreseeable future action, regardless of which agency (Federal or non-Federal) or person undertakes such actions. Cumulative impacts results from individually minor but collectively significant actions taking place over a period of time.

Day 1: Day One, also known as the Closing Date, is the date on which applicants effect the proposed action.

Decibel (dB): A unit of noise measured on a logarithmic scale that compresses the range of sound pressures audible to the human ear over a range from 0 to 140, where 0 decibels represents sound pressure corresponding to the threshold of human hearing, and 140 decibels corresponds to a pressure at which pain occurs. Noise analysts measure sound pressure levels that people hear in decibels, much like other analysts measure linear distances in yards or meters. A-weighted (dBA) refers to a weighting that accounts for the various frequency components in a way that corresponds to human hearing.

Degradation: Changes to a habitat, either terrestrial or aquatic, so that it no longer meets the survival needs of a particular species of plant or wildlife. Such changes could include reducing the feeding area, modifying the vegetation type, and limiting the available shelter.

Dispatcher (train): The railroad operating employee responsible for issuing on-track movement and/or occupancy authority through the use of remotely controlled switches, signals, visual displays, voice control, written mandatory directives, and/or all of the above.

Double-stacked freight service: The transport of two intermodal containers stacked on top of each other on one platform of an intermodal rail flat car.

Emissions: Air pollutants that enter the atmosphere.

Environmental Assessment (EA): A document that the CEQ regulations implementing the National Environmental Policy Act requires Federal agencies to prepare for major projects or legislative proposal having the potential to significantly affect the environment. A tool for decision-making, it describes the positive and negative environmental effects of the undertaking and alternative actions and measures to eliminate potentially significant environmental impacts.

Environmental Justice (EJ): For purposes of this document, The Office of Environmental Analysis (OEA), formerly the Section of Environmental Analysis (SEA), defines environmental justice as the mission discussed in Executive Order (EO) 12898 “Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations” (59 FR 7629, February 11, 1994). This EO directs Federal agencies to identify and address “disproportionately high and adverse human health or environmental effects “of their programs, policies, and activities on minority and low-income populations in the United States. EO 12898 also calls for public notification for environmental justice populations, as well as meaningful public participation of environmental justice populations. In this document, OEA used the guidance provided in the Department of Transportation Order on Environmental Justice, the Council of Environmental Quality’s Environmental Justice: Guidance Under the National Environmental Policy Act, and the Interim Final Guidance for Considering Environmental Justice Concerns Under the National Environmental Act to analyze potential disproportionately high and adverse impacts on environmental justice populations for rail segments, intermodal facilities, rail yards and new construction.

Environmental Justice (EJ) population: A population within an Area of Potential Effect whose minority and low-income composition meets at least one of the following Criteria: (1) the percentage of minority and low-income population in the Area of Potential Effect is greater than 50 percent of the total population in the Area of Potential Effect, or (2) the percentage of minority and low-income population in the Area of Potential Effect is at least ten percentage points greater than the percentage of minority or low income population in the country of which the Area of Potential Effect is a part.

Environmental Resource Score (ERS): The impact Score determined for an environmental resource category within a (block group) area of potential effect. A typical ERS ranges from 0 to 6, reflecting the relative impact on the Area of Potential Effect compared with on other Areas of Potential Effects. For the Environmental Justice analysis, OEA calculates an ERS for noise, hazardous materials transport, and traffic safety and delay.

Equipment: For a railroad, a term used to refer to the mobile assets of the railroad, such as locomotives, freight cars and on track maintenance machines. Also used more narrowly as a collective term for freight cars operated by this railroad.

Executive Order (EO) 12898: Executive Order12898, AFederal Actions to Address Environmental Justice in Minority and Low-Income Populations, issued in February of 1994, directs Federal agencies to identify and address as appropriate “disproportionately high and adverse human health or environmental effects, “including interrelated social and economic effects of their programs, policies, and activities on minority populations and low-income populations in the United States.

Floodplain: The lowlands adjoining inland and coastal waters and relatively flat areas and flood-prone offshore islands, including, at a minimum, those areas that have a 1 percent or greater chance of flood in any given year (also known as a 100-year or a Zone A floodplain).

Fugitive dust: According to EPA regulations, those particulate matter emissions that could not reasonably pass through a stack, chimney, vent or other functionally equivalent opening. Examples of fugitive dust include windborne particulate matter from earth-moving and material handling during construction activities.

Geographic Information System (GIS): A computer system for storing, retrieving, manipulating, analyzing, and displaying geographic data. GIS combines mapping and databases.

Grade crossing: See highway/rail at-grade crossing.

Grade separation: See separated grade crossing.

Gross ton-mile: A measure of railroad production that represents the weight of cars and freight movement in terms of total tons per mile transported system-wide or over a specific rail line segment. Specifically, 1 ton of railroad car and loading carried 1 mile.

Haulage right(s): The limited right (or combination of rights) of one railroad to have its freight traffic moved by another railroad over the designated lines of the railroad.

Hazardous materials: Substances or materials that the Secretary of Transportation has determined are capable of posing an unreasonable risk to human health, safety, and property when transported in commerce, as designated under 49 C.F.R. Parts 172 and 173.

Hazardous wastes: Waste materials that, by their nature, are inherently dangerous to handle or dispose of (e.g., old explosives, radioactive materials, some chemicals, some biological wastes). Usually, industrial operations produce these waste materials. Highway/rail at grade road crossing: The general area of an intersection of a public or private highway and a railroad where the intersecting rail and highway traffic are at the same level.

Historic property: Any prehistoric or historic district, site, building, structure, or object included in or eligible for inclusion in the National Register of Historic Places (NRHP). The term A eligible for inclusion in the NRHP pertains to both properties that the Secretary of the Interior has formally determined to be eligible and to all other properties that meet NRHP listing criteria.

Horn noise (train): Noise that occurs when locomotives sound warning horns in the vicinity of highway/rail at grade crossings.

Hours-of-service regulations: Federal Hours of Service Law, which the Federal Railroad Administration enforces, governing maximum shift lengths and minimum rest periods for railroad operating employees. These employees include train crew, train dispatchers, and signal maintainers, as well as mechanical employees who move equipment for the purpose of testing and inspection.

Inconsistent and Responsive (IR) Application: Proposal to the Surface Transportation Board that Parties of Record request modification of, or alternatives to, proposed action.

Indian tribe: According to Indian Self-Determination and Education : According to Indian Self-Determination and Education Assistance Act (25 U.S.C. Sections 450-458; P.L. 93-638), any Indian Tribe, band, nation, or other organized group or community recognized as eligible for the special programs and services that the United States provides to Indians because of their status as Indians.

Interchange point: Point at which two or more railroads join to exchange freight traffic.

Interlocking: An arrangement of switch, lock and signal devices that is located where rail tracks cross, join, or separate. The devices are interconnected in such a way that their movements must succeed each other in a predetermined order, thereby preventing opposing or conflicting movements.

Intermodal facility: A site consisting of tracks, lifting equipment, paved and/or unpaved areas, and a control point for the transfer (receiving, loading, unloading, and dispatching) of trailers and containers between rail and highway, or between rail and marine modes of transportation.

Key Route: For the purpose of this Draft EA, a rail line segment that carries an annual volume of 10,000 or more carloads of hazardous material.

Key train: Any train with five or more tank carloads of chemicals classified as a Poison Inhalation Hazard (PIH) or with a total of 20 rail cars with any combination of PIHs, flammable gases, explosives, or environmentally sensitive chemicals.

Ldn: The day-night average noise sound level, which is the receptor’s cumulative noise exposure from all noise events over a full 24 hours. This is adjusted to account for the perception that noise at night is more bothersome than the same noise during the day.

Left-hand turnout: See turnout.

Level of Service (LOS): A degree of peak congestion experienced by roadway vehicle traffic stream using procedures that consider factors such as vehicle delay, freedom to maneuver, traffic interruptions, comfort and convenience, and safety. Traffic analysts express LOS as letter grades, ranging from Level of Service A (free flowing) to Level of Service F (severely congested); they measure LOS by the average for all vehicles. Specifically, Level of Service A describes operations with very low delay (less than 5.0 seconds per vehicle) ; Level of Service B describes operations with delay in the range of 5.01 to 15.0 seconds per vehicle; Level of Service C describes operation with delay in the range of 15.0 to 25.0 seconds per vehicle; Level of Service D describes operations with delay in the range of 25.1 to 40.0 seconds per vehicle; Level of Service E describes operations with delay in the range of 40.1 to 60.0 seconds per vehicle; and Level of Service F describes operations with delay in excess of 60.0 seconds per vehicle.

Low-income population: A population composed of persons whose median household income is below the Department of Health and Human Services poverty guidelines.

Mainline: Railroad line that through trains use between terminals. Maintenance area: An area a classified by EPA as meeting National Ambient Air Quality Standards (NAAQS) and which previously (within the last 10 years before reclassification) did not meet NAAQS. Major key route: A rail line segment where the annual volume of hazardous material it carries is projected to double and also exceed 20,000 carloads as a result of the proposed action.

Minority population: A population composed of persons who are Black (non- Hispanic), Hispanic, Asian American, American Indian, or Alaskan Native.

Mitigation: An action taken to prevent, reduce, or eliminate adverse environmental effects.

Motive power: Locomotives operated by the railroad.

Multi-level rail car: A two-level freight car, designed for transporting automotive vehicles.

Multiple Resource Score (MRS): A measure of aggregate impacts used to identify the geographic areas of greatest concern. This score sums the environmental resources scores for hazardous materials transport, noise, and traffic safety and delay and forms the basis for disproportionality.

National Ambient Air Quality Standards (NAAQS): Air pollutant concentration limits established by the EPA for the protection of human health, structures, and the natural environmental.

National Environmental Policy Act (NEPA): The National Environmental Policy Act of 1969, as amended (42 U.S.C. Sections 4321-4347; P.L. 91-190) is the basic national charter for the protection of the environment. It establishes policy, sets goals, and provides means for carrying out the policy. Its purpose is to provide for the establishment of a Council on Environmental Quality and to instruct Federal agencies on what they must do to comply with the procedures and achieve the goals of NEPA.

National Historic Preservation Act (NHPA): The National Historic Preservation Act of 1966, as amended (16 U.S.C. Sections 470-470 et seq.; P.L. 89- 665), is the basic legislation of the Nation’s historic preservation program that established the Advisory Council on Historic Preservation and the Section 106 review process. Section 106 of the NHPA requires every Federal agency to “take into account” the effects of its undertakings on historic properties.

National Priorities List (NPL): A subset of CERCLIS; EPA’s list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under the Superfund Program.

National Register of Historic Places (NRHP): Administered by the National Park Services, the Nation’s master inventory of known historic properties, including buildings, structures, sites, objects, and districts that possess historic, architectural, engineering, archeological, or cultural significance at the Federal, state, and local levels.

Native American: According to the Native American Graves Protection and Repatriation Act of 1990, as amended (25 U.S.C. § 3001 et seq.; P.L. 101-601), of or relating to a tribe, people, or culture that is indigenous to the United States.

Native American lands: According to the regulation of the Advisory Council on Historic Preservation in 36 C.F.R. 800.2 as modified by the scope of the Draft EA, all lands under the jurisdiction or control of an Indian tribe, including all lands within the exterior boundaries of any American Indian reservation.

Negotiated Agreement: An agreement between one or more communities or other governmental units that addresses potential environmental impacts or other issues.

No-action Alternatives: The proposed action does not take place under this alternative; also, the present setting for the pre-action conditions. Noise: A disturbance or annoyance by an unwanted sound. Noise impacts essentially depend on the amount and nature of the intruding sound, the amount of background sound already present before the intruding or unwanted sound occurred, and the nature of work or living activity of the people occupying the area where the sound occurs.

Noise-sensitive receptor: Location where noise can interrupt on going activities and can result in community annoyance, especially in residential areas. The Board’s environmental regulations include schools, libraries, hospitals, residences, retirement communities and nursing homes as examples of noise-sensitive receptors.

Noise contour: Line plotted on a map or drawing connecting points of equal sound levels.

Nonattainment area: An area that EPA has classified as not complying with the National Ambient Air Quality Standards promulgated under the Clean Air Act.

Operating Plan: A document that is provided as part of the proposed application detailing planned railroad by Applicant operations following the proposed action.

Operating practices: Safety and operating rules, practices, and procedures contained in operating rule book, timetable, special instructions or any other company-issued instructions and the management decisions implementing those rules and instructions that govern the movement of trains and work on or around active tracks.

Operating rules: Written rules of a railroad governing the operation of trains and the conduct of employees responsible for train operations when working on or around active tracks.

Particulate matter (PM): Airborne dust aerosols.

Party of Record (POR): A party that notifies the Board of their active participation in a proceeding. When submitting a filing to the Board, the POR must also notify the entire POR service list.

Passive warning devices: Traffic control devices that do not give positive notice to highway users of the approach or presence of a train. These devices may include signs and pavement markings, located at, or in advance of, railroad crossings to indicate the presence of a crossing and the presence of a train. These signs are either regulatory or nonregulatory and may include parallel track signs, crossbucks, stop signs, yield signs, and constantly flashing lights.

Positive train separation: Mechanism included in positive train control, an experimental automated safety system, using Global Positioning System (GPS) technology, onboard computers and wayside information inputs to control train movement. In the event of failure on the primary safety system, positive train control reduces the risk of single-point failure (i.e., human error).

Posted speed: Maximum speed permitted at a specific location on the railroad network irrespective of train type.

Prevention of Significant Deterioration (PSD) Class I Areas: National parks and wilderness areas designated under the Clean Air Act as areas for which users are to maintain air quality at pristine levels, with very small increases in air pollution levels allowed.

Primary Application: The formal filing of documents with the Surface Transportation Board by applicants for railroad mergers, acquisitions, constructions, or abandonments. The Primary Application contains the Operating Plan and information describing related construction projects.

Prime farmland: According to the Natural Resources Conservation Service, land having the best combination of physical and chemical characteristics for producing food, feed forage, fiber, and oilseed crops.

Proposed Acquisition: The proposed acquisition of an entity’s physical assets and operating system for which an Applicant seeks approval from the Board.

Public uses: According to 49 U.S.C. § 10905 and STB Regulations “Surface Transportation Manual,” Section 1105.7 (3)iv those identified alternative public purposes for the use of rail properties proposed for abandonment or discontinuance, including highways, other forms of mass transportation, conservation, energy production or transmission, or recreation.

Queue: A line of vehicles waiting at a highway/rail at-grade crossing for an obstruction to clear.

Rail line segment: For the purposes of this Draft EA, portions of rail lines that extend between two terminals or junction points.

Rail line switch: See turnout.

Rail route: Line of railroad track between two points on a rail system.

Rail yard: A location or facility with multiple tracks where rail operators switch and store rail cars.

Receptor: See noise-sensitive receptor.

Request for Conditions: A document filed with the Board by a party that requests the Board to impose one or more specified requirements on the Applicant as a condition of the Board’s approval of an action.

Resource Conservation and Recovery Information System (RCRIS): Federal database containing information on facilities that generate, transport, store, treat, and/or dispose of hazardous waste.

Resources Conservation and Recovery Act (RCRA): The Resource Conservation and Recovery Act of 1976 (42U.S.C. § 6901 et seq.; P.L. 94-580) is a Federal act governing the generating, storing, transporting, treating, and disposing of hazardous waste.

Responsive Environmental Report (RE): A report, submitted by an Inconsistent or Responsive applicant, that contains detailed environmental information regarding the activities proposed in its IR Application and that complies with the requirements for environmental reports in the Board’s rules at 49 C.F.R. § 1105.7(e).

Retarder: In railroad yards, a braking device, usually power-operated, built into a railroad track to reduce the speed of the cars by means of brake-shoes which, when set in braking position, press against the side of the lower portions of the wheels.

Right-hand turnout: See turnout.

Riparian: Relating to, living or located on, or having access to, the bank of a natural water course, sometimes also a lake or tidewater.

Riprap: A loose pile or layer of broken stones erected in water or on soft ground as a guard against erosion.

Route miles: Length of a railroad line, regardless of the number of tracks.

Safety culture: The manner in which management and employees in an organization view and approach the issue of safety, including both formalized rules and informal practices in the organization.

Safety Integration Plan: Plan that Applicants prepare and submit to the Board to explain how they propose to provide for the safe integration of their separate corporate culture and operating systems if the Board approves the proposed action.

Seamless corridor: A railroad route that does not require cars or blocks of cars to interchange.

Sensitive receptor: See noise-sensitive receptor. Separated grade crossing: The site where a local street or highway crosses railroad tracks at a different level or elevation, either as an overpass or as an underpass.

Service: The official notification and delivery of Board decisions and notices (including environmental documents) by the Secretary of the Board to persons involved in a particular proceeding.

Settlement Agreement: A negotiated agreement between one or more parties, including other railroads, that addresses concerns or requests of the party (or parties). Generally, an agreement addresses competitive customer service or labor issues.

Siding: A track parallel to a main track that is connected to the main track at each end. A siding is used for the passing and/or storage of trains.

Single-line service: Service over one railroad, without having to interchange rail cars between railroads.

Sound Exposure Level (SEL): For a transient noise event such as a passing trains equivalent to the maximum A-weighted sound level that would occur if all of the noise energy associated with the event were restricted to a time period of 1 second. The SEL accounts for both the magnitude and the duration of the noise event; noise analysts use SEL to calculate the day-night average noise level.

Superior train: A passenger train operating on the same track network with freight trains. Superior trains must have track clear of all trains not less than 15 minutes prior to their arrival.

Switch: The portion of the track structure used to direct cars and locomotives from one track to another.

Switching: The activity of moving cars from one track to another in a yard or where tracks go into a railroad customer’s facility.

Tank car: A type of freight car that shippers use to ship liquids and liquefied gases in bulk.

Threshold for environmental analysis: A level of proposed change in railroad activities that determines the need for SEA’s environmental review by the Office of Environmental Analysis (OEA), formerly the Section of Environmental Analysis. OEA first applies the Board’s thresholds for environmental analysis at 49 C.F.R. Part 1105. The Board thresholds apply specifically to air quality and noise.

Ton mile: The movement of one ton of cargo or equipment over a distance of 1 mile.

Track class: Designation between 1 and 6 by the Federal Railroad Administration to characterize the quality and condition of track. The track geometry and type of track structure govern the allowable speed over the track and the level of upkeep to maintain the track. For Class 3 track the maximum allowable operating speed is 40 mph for freight trains and 60 mph for passenger trains. For Class 4 track the maximum allowable operating speed is 60 mph for freight trains and 80 mph for passenger trains.

Train-mile: The movement of one train over a distance of 1 mile.

Turnout: The portion of railroad track structure where a single track divides into two tracks.

Verified Statement: A party’s sworn statement that provides information to the Board. Wayside: Adjacent to the railroad track, as in Awayside signals or Awayside defect detectors.

Wayside noise: Train noise adjacent to the right-of-way that comes from sources other than the horn, such as engine noise, exhaust noise, and noise from steel train wheels rolling on steel rails.

Wetland: According to 40 C.F.R. Part 230.41, those Aareas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions, generally including swamps, marshes, bogs, and similar areas.