Glossary
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| A | |
| AA | Alternatives analysis (related to: EIR) |
| AB3034 | California Assembly Bill 3034 (passed via prop 1A in Nov 2008) which authorizes the sale of $9.95 billion in GO bonds toward the construction of the California HSR network and limited capital improvements to legacy standard-speed rail services. |
| AC | AC Transit (Alameda county) |
| AC | Alternating current |
| ACE | Altamont Commuter Express |
| Acela Express | High speed train service, Amtrak (related to: NEC) |
| AD-# | California assembly district designation |
| aerial | Elevated road or rail alignment supported by concrete pillars for the purpose of grade separation (related to: viaduct) |
| AFAIAC | As far as I am concerned |
| AFAIK | As far as I know |
| AGV | High speed train product family, Alstom |
| alignment | Detailed (lateral and vertical) specification of where rails will run |
| Alstom | Train and systems vendor, France |
| Amtrak | National passenger rail operator, USA |
| Amtrak California | California state passenger rail operator |
| AnsaldoBreda | Train and subsystem vendor, Italy |
| arcing | Undesirable plasma discharge that occurs whenever an active pantograph briefly breaks contact with the OCS, e.g. due to icicles on the wire |
| ARRA | American Recovery and Reinvestment Act (H.R.1-110th) |
| ARTIC | Anaheim Regional Transportation Intermodal Center |
| articulated carriage | see MU |
| ASCE | American Society of Civil Engineers |
| ASME | American Society of Mechanical Engineers |
| at grade | Road or rail alignment at the level of the natural terrain |
| ATC | Automatic Train Control, Japan (related to: PTC) |
| ATO | Automatic Train Operation (related to: PTC) |
| ATP | Automatic Train Protection (related to: PTC) |
| AV | Antelope Valley (Palmdale-Mojave) |
| AVE | High speed train service, Spain |
| axle load | The highest static load supported by any axle on a given vehicle or, the highest such load permitted on a particular (stretch of) track or road |
| B | |
| baby bullet | Caltrain brand name for a standard speed express service level |
| BAC | Bay Area Council |
| BART | Bay Area Rapid Transit (San Francisco Bay Area) |
| berm | See embankment |
| bi-level | Rolling stock featuring two levels of seating above one another |
| BNSF | Burlington Northern Santa Fe railroad |
| BOD | Board of Directors |
| bogie | Assembly of two conventional wheelsets in a frame that can rotate about a vertical axis relative to the vehicle superstructure, required for negotiating relatively tight corners. Wheelsets may be powered. |
| Bombardier | Vehicle and subsystems vendor, Canada (train division headquartered in Germany) |
| bore | Circular tunnel constructed using a TBM. Typically contains one, sometimes two traffic lanes or rail tracks. |
| BRT | Bus Rapid Transit |
| BTW | By the way |
| BUR | Burbank airport |
| C | |
| CA4HSR | Californians for High Speed Rail (advocacy group) |
| CA | California |
| CA-# | California road/freeway designation |
| CAF | Train and subsystem vendor, Spain |
| cant | Angle enclosed by tops of rails and the horizontal plane in a curve |
| CAHSR | California High Speed Rail project |
| CALPIRG | California Public Interest Research Group |
| Caltrain | Regional passenger railroad, San Francisco peninsula |
| Caltrain corridor | Railroad ROW owned by PCJPA. Supports Caltrain and UPRR traffic, selected as preferred alignment for HSR starter line |
| CARRD | Californians Advocating Responsible Rail Design |
| catenary | see OCS |
| CBOSS | Communications-Based Overlay Signal System, Caltrain’s proprietary PTC R&D project |
| CC | Capitol Corridor (Amtrak California route) |
| CC | Contra Costa county |
| CCJPA | Capitol Corridor Joint Powers Authority |
| CEMOF | Caltrain’s Centralized Equipment Maintenance and Operations Facility in San Jose |
| CEQA | California Environmental Quality Act |
| ceramic disk brake | Secondary brake system on HSR trains, mounted on axles. Material resists fading. |
| certification | Assertion by a planning agency that it has complied with NEPA and/or CEQA |
| CHSR | See CAHSR |
| CHSRA | California High Speed Rail Authority |
| CMA | Alameda county transportation authority |
| CO2 | Carbon dioxide |
| coasting | Unpowered travel across the boundary between two electrical segments of the OCS. Breaks are needed to accommodate phase differences in the AC power provided by different generating plants, as well as for maintenance. |
| commuter rail | Passenger rail service operating primarily or exclusively during weekday rush hour |
| consist | Train assembled ad hoc from unpowered rail cars, typically drawn by (a) locomotive(s) |
| corridor | (Pre-existing) major transportation artery plus land to either side |
| coupling | Mechanical connection between two consecutive rail vehicles in a train. May include electrical power and train control connectors for fast assembly/disassembly of complete trains from individual multiple units. |
| CPUC | California Public Utilities Commission, the state-level rail safety regulator |
| CRH-# | High speed train model designation, China |
| CSS | Context Sensitive Solutions, the PRP’s planning method |
| CTC | Centralized Traffic Control (related to: dispatcher) |
| CTCS | Chinese Train Control System (related to: PTC, ETCS) |
| cut-and-cover | Method for constructing a tunnel from above as a trench with a lid |
| cut-and-fill | Method for constructing a shallow trench in which the spoil is used to construct low berms to either side |
| CV | Central Valley (Redding-Sacramento-Bakersfield) |
| D | |
| DB | National railway operator, Germany |
| dB | Decibel, a logarithmic measure of relative signal strength (e.g. sound level) |
| dB(A) | Decibel, weighted using the so-called A-curve to take into account the sensitivity of the human ear as a function of sound frequency |
| DC | Washington, District of Columbia |
| DC | Direct current |
| dead man’s switch | Fail-safe mechanism that automatically engages the emergency brakes on a train unless the driver keeps it depressed |
| DEIR | Draft EIR for public review (related to: CEQA) |
| dispatcher | Operations controller authorized to manage train movements on a line or network |
| DMU | Diesel-hydraulic multiple unit (see MU) |
| deep underpass | Underpass in which the upper road or rail alignment is at grade (see underpass, at grade) |
| DEMU | Diesel-electric multiple unit (see MU) |
| distributed power | See distributed traction |
| distributed traction | Propulsion concept featuring powered axles on multiple cars or locomotives, all controlled by a central computer (see MU) |
| DOT | See USDOT |
| DTS | Decline to state (independent voters in California) |
| DTX | Downtown extension (tunnel in San Francisco) |
| Duplex | Alstom’s bi-level TGV trainset product |
| DX | Desert Express (Las Vegas-Victorville with potential connector to CHSR) |
| E | |
| EB | Eastbound |
| eBART | Project to extend BART service east to Antioch |
| ED | Eminent Domain |
| eddy current brake | Supplemental brake system. Powerful electromagnet can be lowered to just above the top of rail to dissipate kinetic energy by heating the rail. Installed on ICE3 trains, can only be used at sufficiently high speeds. |
| EIR | Environmental Impact Report (related to: CEQA) |
| EIS | Environmental Impact Statement (related to: NEPA) |
| electrification | Engineering project to add an OCS or third rail to a pre-existing rail corridor to enable the operation of electric trains |
| electro-pneumatic brake | Tertiary fail-safe brake system on HSR trains. Latches preventing brake shoes from being pressed against the rims of the wheels are released using locally stored compressed air unless a control current keep the valve in the closed position. On-board batteries prevent accidental triggering during coasting or arcing events. |
| embankment | Artificial earth mound with sloping sides, supporting an elevated road or rail alignment |
| emission | Harmful chemical or noise generated by a given source, e.g. a train |
| EMU | Electric multiple unit (see MU) |
| EPB | Earth Pressure Balance, an efficient TBM variation for soil that is soft but not too wet |
| ERTMS | European Rail Traffic Management System (related to: ETCS, GSM-R) |
| ETCS | European Train Control System (related to: PTC) |
| ETR-# | High speed train model designation, FS (Italy) |
| EU | European Union |
| Eurostar | High speed train service, UK/France |
| Eurostar | High speed train service, Italy |
| express | Train that stops only at major stations along a given route, if any (regardless of route length) |
| F | |
| FAA | Federal Aviation Authority |
| four-quadrant operation | Characteristic of power converter capable of operating an electric machine in both motor and generator modes, in both rotation directions |
| FONSI | Finding of No Significant Impact (related to: CEQA) |
| FRA | Federal Railroad Administration (part of USDOT) |
| FS | National railway operator, Italy |
| FSSF | Fast-slow-slow-fast (related to: track order) |
| FTA | Federal Transit Authority (part of USDOT) |
| FUD | Fear, uncertainty and doubt |
| FWIW | For what it’s worth |
| FY | Fiscal Year |
| FYI | For Your Information |
| G | |
| GO 26-D | General Order 26-D governing rail station platform heights in California (related to CPUC) |
| GO bonds | General obligation bonds sold by the state of California, serviced out of the General Fund (i.e. general state tax revenue). Voters must authorize the sale by passing a proposition by simple majority before the state legislature can actually appropriate some or all of the bonds in the context of a balanced budget, which it must pass with a 2/3 supermajority. |
| grade separation | Civil engineering structure with cross traffic lanes and/or tracks at different vertical elevations at an intersection |
| gradient | Tangent of the angle enclosed by the slope of a rail alignment and the horizontal plane. Must be corrected upward if the alignment is also curved. |
| GSM-R | Highly reliable terrestrial wireless signaling technology, Europe |
| H | |
| HBF | Hauptbahnhof (German for main/central train station) |
| headway | Time difference for the front ends of two consecutive trains passing a fixed location |
| hikari | Limited stop train, Japan (related to: shinkansen, limited) |
| Hitachi | Train and subsystem vendor, Japan |
| HMF | Heavy maintenance facility |
| HNTB | A US infrastructure planning and construction company |
| HSIPR | High Speed Intercity Rail Program, run by the FRA |
| HSR | High Speed Rail (over 110mph in the US, over 200 km/h elsewhere) |
| HSRA | See CHSRA |
| HST | High Speed Train (related to: HSR) |
| H.R. # | House Resolution designation (federal bill) |
| HRT | Heavy rail transit (high-capacity public transportation systems such as subways, commuter/regional rail and intercity rail, typically 4 or 5 seats abreast, often partially or fully grade separated in built-up areas) |
| HRV | Heavy rail vehicle (complete train, trainset, locomotive or individual passenger/freight car) |
| Hwy # | Highway designation |
| I | |
| I-# | Interstate freeway designation |
| ICE# | High speed train model designation, Germany |
| IE | Inland Empire (roughly, Ontario-San Bernardino-Riverside) |
| immission | Sum total of harmful chemicals or noise received at a particular location from all sources |
| IMHO | In my humble opinion |
| IMO | In my opinion |
| induction motor | Highly robust electric machine, relies on frequency differential between stator and rotor three-phase currents to produce torque, therefore less efficient than synchronous motors. Typically deployed with a fixed ratio final drive gear box to reduce motor size and weight in powered bogies. |
| intercity rail | Passenger rail service, typically with routes over 100 miles long |
| inverter | Solid-state electrical machine that uses variable PWM to convert DC current into approximately sinusoidal three-phase AC current of any desired frequency in a defined range. Used for continuously variable motor speed control. |
| ITS | Institute for Transportation Studies, University of California at Berkeley |
| J | |
| jackknifing | Conventional rail cars rotating to extreme angles relative to the tracks after a derailment, leading to capsizing and/or crushing of the superstructure. Greatly increases the risk of injuries and casualties in passenger rail contexts. |
| Javelin | High speed train service, UK |
| Jacobs bogie | Bogie located in-between short rail cars to reduce the risk of jackknifing in the event of a derailment (related to: Alstom) |
| JR | Collection of regional railway operators, Japan |
| K | |
| Kawasaki | Train and subsystem vendor, Japan |
| km/h | Kilometers per hour (1 km/h = ~0.6 mph) |
| kodama | Local train, Japan (related to: shinkansen, local) |
| KTX-# | High speed train model designation, South Korea |
| kV | Kilovolt |
| L | |
| LA | Los Angeles |
| LACMTA | Los Angeles County Metropolitan Transportation Authority (see also: MTA) |
| LA Metro | Local transit operator in the city and county of Los Angeles |
| LAUS | Los Angeles Union Station |
| LAWA | Los Angeles World Airports |
| LAX | Los Angeles airport (related to: LAWA) |
| Leq | Equivalent sound level, computed by averaging over a defined time interval and expressed in dB(A). Used to objectively assess noise immissions in the context of environmental reviews, relative to pre-defined thresholds. |
| lid | Concrete slab covering a (section of a) trench (related to: cut-and-cover) |
| limited | Train that stops at most stations along a given route (regardless of route length) |
| LGV | Ligne à grande vitesse (dedicated high speed line, France) |
| local | train that stops at all stations along a given route (regardless of route length) |
| LOSSAN | Los Angeles-Anaheim-San Diego rail corridor along I-5 |
| LPA | Locally preferred alternative |
| LRT | Light rail transit (urban/suburban trams, max. speed 55mph, typically 3 seats abreast and room for standees, typically electrified via OCS, may operate in streetcar mode if LRVs are short enough) |
| LRV | Light rail vehicle (typically articulated to negotiate tight corners) |
| M | |
| MB | Mission Bay (San Francisco neighborhood adjacent to Caltrain’s 4th & King terminus) |
| Metrolink | Regional passenger rail operator, southern California |
| MP | Menlo Park |
| mph | Miles per hour (1 mph = ~1.6 km/h) |
| MTA | Metropolitan Transportation Authority, New York City (see also LACMTA) |
| MTC | Metropolitan Transportation Commission for the San Francisco Bay Area |
| MU | multiple unit (articulated passenger rail vehicle, typically self-propelled and with driver cabs at either end) |
| Muni | Municipal transportation authority and operator, San Francisco |
| N | |
| NB | Northbound |
| NCTD | North Coast Transportation Division (San Diego county) |
| NEC | Northeast Corridor (USA) |
| NEPA | National Environmental Policy Act |
| NIMBY | Not In My Back Yard |
| Nippon Sharyo | Train and subsystem vendor, Japan |
| NJT | New Jersey Transit (related to: NEC) |
| NorCal | Northern California |
| nozomi | Express train, Japan (related to: shinkansen, express) |
| NPV | Net Present Value, relates past or future sums to present day by accounting for inflation |
| NRPC | National Railroad Passenger Corporation (Amtrak’s legal parent organization) |
| NTV | Private HSR operator, Italy |
| O | |
| OAC | Oakland Airport Connector (related to: BART) |
| objective metric | Reliably repeatable physical measurement using an inanimate device |
| OAK | Oakland airport |
| OC | Orange county (southern California) |
| OCTA | Orange County Transportation Authority |
| OCS | Overhead catenary system |
| ONT | Ontario airport (related to: LAWA) |
| OT | Off topic |
| overpass | Grade separation in which a road crosses another road or rail alignment via an aerial |
| P | |
| PA | Palo Alto |
| pantograph | Articulated mechanism that provides the electrical connection between a (moving) train and the stationary grid (related to: OCS) |
| PAMPA | Palo Alto, Menlo Park and Atherton |
| passenger rail | Transportation of humans, pets and personal belongings on a train. Typically a for-fee service, often subsidized by taxpayers to reduce road congestion and/or improve air quality. |
| PB | See PBQD |
| PBQD | Parsons, Brinckerhoff, Quade and Douglas |
| PCC | Peninsula Cities Coalition (San Francisco peninsula) |
| PCJPB | Peninsula Counties Joint Powers Board (related to: Caltrain) |
| Pendolino | High speed train product family with active tilt (related to: Alstom) |
| platform height | Vertical distance between top of rail and the edge of the platform |
| PMD | Palmdale airport (related to: LAWA) |
| PMSM | Permanent Magnet Synchronous Motor, based on rare-earth ferromagnetic materials and control coils to manage the magnetization level. Some designs can be attached directly to HSR wheelsets, without a final drive gear box. |
| power | Physical quantity representing energy flow per unit of time. May be expressed as e.g. force times speed, torque times radial velocity, voltage times current. |
| power converter | Solid-state electrical machine combining a rectifier and an inverter |
| power diode | Special large semiconductors designed to permit high currents to flow in one direction only. Require forced cooling. (related to: rectifier) |
| power transistor | Special large semiconductors designed to switch high voltages and/or currents at various frequencies. Require forced cooling. (related to: inverter) |
| PPP | Public-Private Partnership, a funding mechanism |
| PRIIA | Passenger Rail Investment and Improvement Act (H.R.2095-110th) |
| PRP | Peninsula Rail Program, planning body for the SF peninsula staffed jointly by Caltrain and CHSRA |
| prop | (California) ballot proposition |
| PS | Pacific Surfliner (Amtrak California route) |
| psychoacoustics | Scientific study of how sounds are perceived by the human brain. Generally not used for environmental impact assessments as perception is based on subjective metrics. |
| PTC | Positive Train Control, a combination of fixed and in-cab technology that can override driver control to ensure trains cannot exceed speed limits or run red lights (related to: PRIIA) |
| PUC | See CPUC |
| PWG | Policy Working Group, part of PRP |
| PWM | Pulse Width Modulation, a method of controlling electrical current amplitude by using power transistors to interrupt the circuit for a defined fraction of a recurring very short interval |
| Q | |
| Quantm | Alignment optimization software, Trimble Corporation |
| R | |
| railroad tie | Wooden, concrete or steel element installed perpendicular to the rails to maintain the gauge and distribute the load as a train passes the location |
| rail yard | Facility at which locomotives and/or rolling stock are stabled (parked), maintained and/or assembled into trains |
| RC | Reverse condemnation (related to: ED) |
| rectifier | Solid-state electrical machine that generates approximately DC current from AC current of any frequency. Used to supply inverters. |
| recuperative braking | Primary brake mechanism for electric trains. Motors are operated in generator mode and the power fed back into the grid, provided it can immediately be used for the propulsion of some other train on the same electrical segment. Works best on busy lines. |
| RENFE | National railway operator, Spain |
| retained fill embankment | Embankment with straight sides contained within concrete walls to reduce lateral footprint |
| reverse split grade | Grade separation in which a road crosses a moderately depressed road or rail alignment via a low overpass |
| RFF | National rail grid operator, France |
| rheostat | Secondary brake system on HSR trains. Essentially, giant force-cooled ohmic resistors, typically mounted on the roof of the vehicle. Only used if the OCS cannot accept (all of) the electricity produced by the electric motors in generator mode. |
| ROD | Record of decision (endorsement of EIS by authorized federal agency) |
| ROTEM | Train and subsystem vendor, South Korea |
| route | Rough (lateral) specification of where rails will run, e.g. which cities will be connected |
| ROW | Right of way |
| RR | Railroad (generic) |
| RT | Sacramento Regional Transit |
| ruling gradient | The largest gradient on a given route (see gradient) |
| RWC | Redwood City |
| S | |
| S. # | US senate bill designation |
| Sac | Sacramento |
| SAN | San Diego airport (Lindbergh Field) |
| SANDAG | San Diego Association of Governments |
| San Diego trolley | Local transit operator in the city and county of San Diego |
| Sapsan | High speed train service, Russia (related to: Velaro) |
| SB | California senate bill |
| SB | San Bernardino |
| SB | Southbound |
| SCAG | Southern California Association of Governments |
| SCRRA | Southern California Regional Railway Authority (related to: Metrolink) |
| SDMTS | San Diego Metropolitan Transity System |
| SEPTA | Southeastern Pennsylvania Transportation Authority (related to: NEC) |
| SF | San Francisco |
| SFFS | Slow-fast-fast-slow (related to: track order) |
| SFO | San Francisco airport |
| SFTT | See TTC |
| shinkansen | Dedicated high speed line or train, Japan |
| Siemens | Train and systems vendor, Germany |
| SJ | San Jose |
| SJ | San Joaquin (Amtrak California route) |
| SJ | National railway operator, Sweden |
| SJC | San Jose airport |
| sleeper | See railroad tie |
| SMART | Sonoma-Marin Train |
| SMCTA | San Mateo County Transportation Authority |
| SMF | Sacramento International Airport |
| SNCF | National railway operator, France |
| SoCal | Southern California |
| SP | Southern Pacific (related to: UPRR) |
| split grade | Grade separation in which a road crosses a moderately elevated road or rail alignment via a shallow underpass |
| S.R.-# | State Route designation |
| stabling yard | Parking lot for locomotives and/or rolling stock (related to: rail yard) |
| standard speed | Trains and/or rail corridors operating at speeds below HSR levels (see HSR for thresholds) |
| starter line | Initial route of a planned rail network. For California HSR, AB3034 defines this as “San Francisco Transbay Terminal to Los Angeles and Anaheim”. |
| streetcar mode | Train running on track section embedded in a road lane. Only permitted for LRT in new construction in the US. |
| subjective metric | Physical measurement based on the average assessment of a group of specially trained persons |
| subway | Urban/suburban HRT, fully grade separated, typically even against other lines on the same network |
| subway tunnel | See cut-and-cover |
| superelevation | See cant |
| switching power supply | Solid-state electrical device combining power semiconductors and a transformer operating at very high frequency. Slightly less efficient than a regular transformer but light and compact enough to permit passenger seating in all cars of an HSR trainset. |
| synchronous motor | Highly efficient electric machine featuring stator and rotor three-phase currents of the exact same frequency |
| T | |
| TALGO | Train and equipment vendor, Spain |
| TBD | To be determined |
| TBM | Tunnel boring machine |
| TBT | See TTC |
| tilt | Mechanism for improving lateral acceleration comfort for passengers and hence, feasible speed, in relatively tight curves with insufficient physical cant. Passive for TALGO, otherwise active. |
| timetable | Schedule detailing when and where trains are supposed to stop at stations along a given route |
| TGV | Train à grande vitesse (high speed train in France, usually made by Alstom) |
| Thalys | High speed train service, France/Belgium/Netherlands |
| third rail | Electrical power supply installed at rail level. Cheaper and more compact than OCS, but grade separation required for pedestrian safety. Modest maximum voltage and hence power. Commonly used for subway systems. |
| THSR | Taiwan High Speed Rail |
| TJPA | Transbay Joint Powers Authority (San Francisco) |
| TOD | Transit-oriented development |
| top of rail | Reference elevation for equipment and platform design |
| track order | Track assignment for fast HSR/express commuter and slower local commuter/freight services in a quad track context |
| trainset | Aerodynamically optimized high speed multiple unit (see MU) |
| transformer | Solid-state electrical device for converting between AC voltages |
| transit | Local public transportation, typically subsidized by taxpayers and based on a combination of fixed-route buses, LRT and HRT with transfer stations |
| trench | Excavated ditch containing a road or rail alignment. May feature sloping earthen sides or concrete side walls. May be covered with lids. |
| trolley | See LRT |
| truck | See bogie |
| TT | See TTC |
| TTC | Transbay Terminal Center (related to: TJPA) |
| TTT | See TTC |
| tunnel | Underground road or rail alignment, enclosed on all sides |
| tunnel boom | Acoustic funnel effect at tunnel portals, increasing both volume and duration of environmental sound events |
| tunnel portal | Structure terminating a tunnel where it emerges back above ground |
| TVM-430 | PTC implementation, France |
| TWG | Technical Working Group, part of PRP or CHSRA planning effort |
| U | |
| underpass | Grade separation in which a road crosses another road or rail alignment in a very short tunnel |
| UP | See UPRR |
| UPRR | Union Pacific Railroad |
| US-# | Federally funded freeway designation (related to: I-#) |
| USDOT | US Department of Transportation |
| V | |
| Velaro | High speed train product family, Siemens |
| VHSR | Very High Speed Rail (over 300 km/h = 186 mph) |
| viaduct | Elevated road or rail alignment supported by concrete pillars for the purpose of maintaining grade across a depression or valley in the topography (related to: aerial) |
| VTA | Valley Transportation Authority for Santa Clara county |
| W | |
| WB | Westbound |
| WB | World Bank |
| WETA | Water Emergency Transportation Authority (SF Bay ferries) |
| wheelset | Rigid assembly of two steel railroad wheels and an axle |
| wheelset | Assembly of a U-shaped frame and two individual unpowered steel railroad wheels and axles (TALGO only) |
| WiFi | Family of wireless local area network standards (IEEE 802.11) |
| WSX | Warm Springs Extension (project to extend BART to Alameda county border in Fremont) |
| X | |
| X-2000 | High speed train service on heavy freight lines, Sweden |
| Y | |
| yard | See rail yard |
| YOE | Year of Expenditure |
| Z | |
| Zefiro | High speed train product family, Bombardier |
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