Glossary

  • Adhesion railway – a railway which relies on friction between wheels and rails for traction. Contrast with rack or cog railway, also maglev.
  • AECOM13 – The High Speed Rail Study Phase 2 Report by AECOM, commissioned by the Rudd government and released in April 2013.
  • Alignment – The three-dimensonal geometry of track layout – a combination of vertical alignment, horizontal alignment and cant.
  • ARUP01 – The East Coast Very High Speed Train Scoping Study by Arup and TMG, commissioned by the Howard government and released in November 2001.
  • At-grade – refers to railroad or other infrastructure (typically intersections) built at ground level. Includes cuttings and embankments but excludes bridges and tunnels. See also level crossing.
  • Balise – an electronic transponder placed between rails to allow central monitoring of the position of the train in the rail network.
  • Ballast – The trackbed upon which sleepers and rails are laid. Typically made of crushed stone.
  • Ballastless track – A track system in which no ballast is required. Rails are typically fastened directly to a concrete slab.
  • Bogie – A structure underneath a train to which wheels are attached; it can pivot to allow smooth cornering. Can also contain suspension and/or tilting mechanism
  • Branch line – A secondary rail line which branches off from a more important line, usually a mainline. A short branch line may be called a spur line, especially if having only one station.
  • BZE14 = The 2014 report Zero Carbon Australia: High Speed Rail by advocacy group Beyond Zero Emissions.
  • Cant – The difference in height between the outer and inner rails of a curve. Measured in millimetres.
  • Cant Deficiency – The amount of extra cant required to balance all centrifugal forces when taking a curve at the design speed.
  • Capping – the upper layer of trackbed; also called blanket.
  • Catenary – See OHLE.
  • Corridor – See Right-of-Way.
  • Cut – an area of excavated soil or rock used to avoid or reduce the steepness of an increase of elevation required by terrain. See also Embankment.
  • Deviation – a new section of railroad built to avoid a slower or otherwise undesirable existing section, .
  • Down – the track direction away from a major destination (usually the hub-city of a rail network). Synonymous with outbound.
  • Distributed power – refers to distribution of driving carriages throughout a train; may be through use of multiple-units, or locomotives placed at the middle or end of a train.
  • DMU – Diesel Multiple Unit; a multiple-unit train powered by diesel engines
  • Dormitory town – a city or suburb in which a large proportion of the residents work elsewhere. Also known as commuter town, bedroom town and exurb.
  • Embankment – an area of compacted soil or fill used to avoid or reduce the steepness of a lowering of elevation required by terrain. See also Cut.
  • EMU – Electric Multiple unit; a multiple-unit train powered by overhead lines.
  • Express train – a train which passes some or all intermediate stations without stopping.
  • Exurb – see dormitory town.
  • Fallen flag – North American term referring to a railroad company or track which is now defunct.
  • Fill – see Embankment.
  • Flag stop – a small railway station at which the train only stops by request. Named for the practice of using a flag at the station to signal the driver; electronic signals are often used in modern times. See also Halt.
  • Gauge – The distance between the inner edges of load-bearing rails. Standard Gauge is 1435mm.
  • Grade – The vertical slope of the railway. Historically quoted as a ratio of “rise over run”, it is now more commonly quoted as a percentage.
  • Grade separation – A method of aligning a junction of two transport ways (eg, road and rail) at different heights, such that one does not have to yield to the other.
  • Halt – a small railway station with no staff and few or no facilities. Trains often stop by request only; see flag stop.
  • Head-end power – system where electrical power for lighting, heating and other ancillary train functions is supplied by a generator in the locomotive or “head” of the train.
  • High-speed rail – A rail system with a design speed of 200km/h or over (if upgraded from an existing railway) or 250km/h or over (if purpose-built).
  • Horizontal alignment – the planform of a rail alignment (as if viewed from above). Constrained by radius of curvature and transition curves.
  • Level crossing – An intersection between road and rail which crosses at the same level. They may have automated barriers, lights, or warning signs. See also at-grade.
  • MagLev – Magnetic Levitation; a method of train propulsion whereby the train is suspended by powerful electromagnets over a specialised track.
  • Mainline – the through-line(s) at a railway station or any location with sidings. Can also refer to the principle rail artery in a large railway system.
  • Mainspan – the largest distance between supports for a bridge or beam.
  • Multiple unit – self-propelled rail carriage capable of being coupled with other similar units and being controlled from a driving cab.
  • OHLE – Overhead Line Equipment – the overhead wire supplying power to electric trainsets.
  • Pantograph – An apparatus to maintain contact between the train and the catenary wire.
  • Passing loop – on single-track railway, refers to a short section of double-track allowing trains to pass one-another
  • Permanent way – The railway track itself, consisting of rails, fasteners, sleepers, ballast or slab, and subgrade earthworks.
  • Rack railway – a railway which uses a third “rack” rail and a driving cog to allow use on steep grades (typically >7%). Also known as cog railway. Contrast with adhesion railway.
  • Right-of-way – An easement of land reserved for transportation purposes.
  • Rollingstock – The vehicles that move on a railway. Although the UK uses the term “rollingstock” to refer specifically to unpowered vehicles, Hot Rails uses it in the American sense to refer to all rail vehicles.
  • Section – Used in this blog to refer to a short length of railway, analysed on its own within a larger post. Typically defined by a length of alignment having similar engineering requirements, and 1-5km in length (rarely much longer). Subset of Sector.
  • Sector – Used in this blog to refer to a length of railway considered for analysis in a single post. Usually a length between stations or other major landmarks, typically between 10 and 25km apart.
  • Side-line – A section or rail off the mainline, typically used to access a station where a through-line would be impractical. Contrast with through-line.
  • Siding – a section of rail off the mainline, typically used for sorting or storing rollingstock, allowing trains to pass, or accessing facilities.
  • Slab track – see Ballastless track
  • Speedrail – A mid-1990s proposal for a high-speed railway from Sydney to Canberra.
  • Superelevation – See cant.
  • SWRL – South West Rail Link, a suburban railway line in Sydney’s southwest near Glenfield.
  • SWSR – Steel wheel, steel rail; shorthand for conventional rail technology.
  • Terminus – a station at the end of the railway line.
  • Through-line – A rail line allowing trains to pass through or adjacent a station without stopping, often at high speed. Contrast with side-line.
  • Trainset – a set of rollingstock either permanently or semi-permanently configured as a unified set of equipment. Most often applied to passenger trains.
  • Trackbed – the foundation of a railway track, between ballast and natural ground.
  • Transition curve – a curve of varying radius used to transition from straight to constant-radius curved track. Typical geometry is an Euler spiral.
  • Turnout – a section of railroad allowing trains to transfer from one track to another.
  • Up – the track direction towards a major destination (usually the hub city of the rail network). Synonymous with inbound.
  • Vertical alignment – the elevation profile of a rail alignment. Grade and vertical radius (rate of change of grade) determine the vertical alignment.
  • VFT – the Very Fast Train Joint Venture, a proposal for a high-speed railway from Melbourne to Brisbane via Canberra and Sydney from the late 1980s. Also used in Australia as a synonym for High Speed Rail.
  • Viaduct – a bridge composed of several spans used for crossing a valley or gorge, or for reducing the grade required to change the altitude of the alignment.
  • Yard – a location where rollingstock is assembled into trains. Usually located at stations and consists of several sidings and switches.

 

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