A ballastless track or slab track is a type of
railway track
A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleepers, ...
infrastructure in which the traditional elastic combination of
ties/sleepers and
ballast
Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, ...
is replaced by a rigid construction of
concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...
or
asphalt
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...
.
Characteristics
In ballastless tracks, the
rails
Rail or rails may refer to:
Rail transport
*Rail transport and related matters
*Rail (rail transport) or railway lines, the running surface of a railway
Arts and media Film
* ''Rails'' (film), a 1929 Italian film by Mario Camerini
* ''Rail'' ( ...
are rigidly fastened to special types of concrete ties/sleepers that are themselves set in concrete. Ballastless tracks therefore offer a high consistency in
track geometry
Track geometry is concerned with the properties and relations of points, lines, curves, and surfaces in the three-dimensional positioning of railroad track. The term is also applied to measurements used in design, construction and maintenance of t ...
, the adjusting of which is not possible after the concreting of the superstructure. Therefore, ballastless tracks must be concreted within a tolerance of .
The elasticity of the ballast in the traditional railway superstructure is replaced by flexibility between either the rails and the concrete ties/sleepers or the ties/sleepers and the concrete or asphalt slab as well inherent elasticity within the conglomerate of the tie/sleeper, whereas the concrete or asphalt slab is usually inelastic.
Advantages
The advantages of a ballastless track over a traditional superstructure are its highly consistent track geometry, its longer life span, and the reduced need for
maintenance
Maintenance may refer to:
Biological science
* Maintenance of an organism
* Maintenance respiration
Non-technical maintenance
* Alimony, also called ''maintenance'' in British English
* Champerty and maintenance, two related legal doctrine ...
.
A ballastless track’s track geometry is achieved mainly due its relative inelasticity in comparison to a traditional superstructure that results in far fewer deformations and generally smoother running;
train drivers (engineers) of the
London Overground
London Overground (also known simply as the Overground) is a Urban rail in the United Kingdom, suburban rail network serving London and its environs. Established in 2007 to take over Silverlink Metro routes, (via archive.org). it now serves a ...
's
East London Line have informally declared the Low Vibration Track system as the smoothest superstructure they have experienced. Measurements conducted in Switzerland in 2003 and 2004 showed a standard deviation of the gauge of less than .
This in turn increases the track’s life span and reduces the need for maintenance. The usual preventive maintenance is limited to rail grinding, since
tamping is not necessary due to the absence of ballast. Curative maintenance beyond rail replacement is required only after several decades. The
Swiss Federal Railways
Swiss Federal Railways (german: link=no, Schweizerische Bundesbahnen, ''SBB''; french: link=no, Chemins de fer fédéraux suisses, ''CFF''; it, Ferrovie federali svizzere, ''FFS'') is the national railway company of Switzerland. It is usuall ...
replaced the ties/sleepers and rubber shoes of the ballastless track in the -long
Heitersberg Tunnel
The Heitersberg railway line (''Heitersbergstrecke'') is a Swiss railway line between the stations of Killwangen-Spreitenbach and Aarau on the east-west main line between Zürich and Bern. The main structure of the line is the 4,929 metre-long He ...
between 2014 and 2016, whereas no maintenance of the concrete slab was necessary 39 years after the tunnel’s opening.
Due to its good experiences with the system, the Swiss Federal Railways are looking to install ballastless track wherever there is a rigid substructure—in tunnels as well as on
viaduct
A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide v ...
s.
Further advantages of ballastless tracks include better and controlled
drainage
Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess of water. The internal drainage of most agricultural soils is good enough to prevent severe waterlogging (anaerobic conditio ...
, the elimination of flying-ballast damage on
rolling stock
The term rolling stock in the rail transport industry refers to railway vehicles, including both powered and unpowered vehicles: for example, locomotives, freight and passenger cars (or coaches), and non-revenue cars. Passenger vehicles can b ...
and
civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewage ...
structures, a shallower superstructure, and the possibility of run-over sections such as
crossings over which
pneumatic vehicles can be driven. When used in stations, ballastless tracks are easier to clean.
Disadvantages
The primary disadvantage of a ballastless track is its significantly higher cost of initial construction. While numbers vary depending on construction type and track infrastructure (ballastless tracks are generally more suitable to infrastructures that are also made of concrete, as is the case in tunnels or on viaducts), the
Deutsche Bahn
The (; abbreviated as DB or DB AG) is the national railway company of Germany. Headquartered in the Bahntower in Berlin, it is a joint-stock company ( AG). The Federal Republic of Germany is its single shareholder.
describes itself as the se ...
estimated in 2015 that construction costs of ballastless tracks are 28 percent higher than those of traditional superstructure. However, the
life-cycle cost
Whole-life cost is the total cost of ownership over the life of an asset. The concept is also known as life-cycle cost (LCC) or lifetime cost, and is commonly referred to as "cradle to grave" or "womb to tomb" costs. Costs considered include the f ...
of ballastless tracks are generally lower than those of ballasted tracks due to significantly lower maintenance.
Further disadvantages of ballastless tracks are the impossibility of adjusting or correcting track geometry once concrete has been set, the necessity of a stable infrastructure (since no adjustments can be made to the superstructure), higher noise emissions, and longer repair times when the concrete slab is damaged (e.g. due to construction faults or wear and tear).
Construction Types
Early slab track projects a range of construction types, sub-bases and fastening technologies. The following list contains construction types of ballastless tracks that have been internationally used in heavy-rail systems (as opposed to
light railway
A light railway is a railway built at lower costs and to lower standards than typical "heavy rail": it uses lighter-weight track, and may have more steep gradients and tight curves to reduce civil engineering costs. These lighter standards allow ...
s,
tram
A tram (called a streetcar or trolley in North America) is a rail vehicle that travels on tramway tracks on public urban streets; some include segments on segregated right-of-way. The tramlines or networks operated as public transport are ...
ways, or
metros) in chronological order of their first usage.
SBB Bözberg/STEDEF (SBB)
The Bözberg/STEDEF system consists of twin ties/sleepers that are connected by a steel track rod and enclosed in a rubber shoe. All of its components can be exchanged individually. Bözberg/STEDEF was first used by the Swiss Federal Railways in the
Bözberg tunnel in 1966.
STEDEF was further developed by SATEBA prior to the system’s installation on the French
LGV Méditeranée.
Rheda (Rail.One)
The Rheda system consists of three layers: a base course and two slabs that are joined by
rebar
Rebar (short for reinforcing bar), known when massed as reinforcing steel or reinforcement steel, is a steel bar used as a Tension (physics), tension device in reinforced concrete and reinforced masonry structures to strengthen and aid the concr ...
s, as are the individual ties/sleepers. Rheda was first used by the Deutsche Bahn in
Rheda-Wiedenbrück station
Rheda-Wiedenbrück station is a passenger station in the Westphalian town of Rheda-Wiedenbrück in the German state of North Rhine-Westphalia. It lies on the Hamm–Minden railway, one of the most heavily trafficked lines in Germany. The Warendorf ...
, after which it is named, in 1972. It has since been installed on the Dutch
HSL-Zuid route between
Amsterdam
Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the Capital of the Netherlands, capital and Municipalities of the Netherlands, most populous city of the Netherlands, with The Hague being the seat of government. It has a population ...
and
Rotterdam
Rotterdam ( , , , lit. ''The Dam on the River Rotte'') is the second largest city and municipality in the Netherlands. It is in the province of South Holland, part of the North Sea mouth of the Rhine–Meuse–Scheldt delta, via the ''"N ...
, in the Spanish
Guadarrama
Guadarrama is a town and municipality in the Cuenca del Guadarrama comarca, in the Community of Madrid, Spain.
Its population is 13,032 (winter, according to a 2006 census); the population swells to approximately 60,000 in summer.
Its name co ...
and
Sant Joan Despí
Sant Joan Despí (; ) is a city and municipality located in the Baix Llobregat area ( Barcelona province in Catalonia, Spain). It is situated on the left bank of the Llobregat river. ''Es'' is a dialectal form of the masculine article ''el'', hen ...
tunnels, and on various Chinese high-speed lines including
Wuhan–Guangzhou High-Speed Railway
The Wuhan–Guangzhou high-speed railway, also called the Wuguang high-speed railway and short for Beijing–Guangzhou–Shenzhen–Hong Kong high-speed railway, Wuhan–Guangzhou section, is a high-speed rail line, operated by China Railway H ...
.
Bögl (
Max Bögl
Max Bögl is a German multinational major construction company based in Sengenthal, Germany.__NOTOC__
Projects
The company has carried out several major projects in transport infrastructure, civil engineering and sport venues. It has also paten ...
)
The Bögl ballastless track is characterised by its use of
prefabricated
Prefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is u ...
concrete slabs in lieu of a continuous structure that is cast on site.
Mortar is used to connect the 9-ton-slabs to the infrastructure and to one another. The Bögl system was developed in Germany and first tested in
Dachau in 1977. The first serial installation took place in
Schleswig-Holstein
Schleswig-Holstein (; da, Slesvig-Holsten; nds, Sleswig-Holsteen; frr, Slaswik-Holstiinj) is the northernmost of the 16 states of Germany, comprising most of the historical duchy of Holstein and the southern part of the former Duchy of Sch ...
and
Heidelberg
Heidelberg (; Palatine German language, Palatine German: ''Heidlberg'') is a city in the States of Germany, German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914 ...
in 1999. For its use on the
high-speed link between Beijing and Shanghai, 406,000 slabs were installed.
FF ÖBB/PORR (
PORR
Porr AG (referred to by the company as PORR AG) is a construction group listed on the Vienna Stock Exchange with its headquarters in Vienna. It is one of the largest Austrian construction companies and is active nationally and internationally in a ...
)
The ÖBB/PORR ballastless track (FF stands for German ''Feste Fahrbahn'', meaning ''ballastless'' or, literally, ''fixed track'') consists of an elastically supported track slab. It was first tested in 1989, became the standard system in Austria in 1995, and has been used for over 700 kilometres of track worldwide, including the German Verkehrsprojekt Deutsche Einheit Nr. 8 (German Unity Transport Project 8) and the
Doha metro
The Doha Metro is a rapid transit system in Doha, Qatar's capital city, which became operational on 8 May 2019. It has three lines with an approximate overall length of 76 km and 37 stations. It is an integral component of the larger Qata ...
. The system will be used on the first phases of the United Kingdom's
High Speed 2
High Speed 2 (HS2) is a planned high-speed railway line in England, the first phase of which is under construction in stages and due for completion between 2029 and 2033, depending on approval for later stages. The new line will run from its m ...
line, except in tunnels and for some specialist structures.
Low Vibration Track (Sonneville/Vigier Rail)
The Low Vibration Track (LVT) system is similar to Bözberg/STEDEF in that it also uses twin ties/sleepers enclosed in rubber shoes.
However, LVT does not feature a tie rod.
The system was developed and tested by Roger Sonneville together with the Swiss Federal Railways in the 1990s
before the rights were sold to Vigier Rail in 2009. LVT has been in service in the
Channel tunnel
The Channel Tunnel (french: Tunnel sous la Manche), also known as the Chunnel, is a railway tunnel that connects Folkestone (Kent, England, UK) with Coquelles ( Hauts-de-France, France) beneath the English Channel at the Strait of Dover. ...
since 1994. Due to the tunnel’s German name ''Eurotunnel'', LVT is sometimes referred to as Euroblock. LVT has been used for over 1300 kilometres of track worldwide, including the Swiss
Lötschberg
The Lötschberg is an Alpine mountain massif and usually associated with a major, historically important transit axis of the Alps in Switzerland with, at its core, the Lötschen Pass (german: Lötschenpass, Swiss German: ''Lötschepass''). The m ...
,
Gotthard and
Ceneri base tunnels, the South Korean
high-speed Suin Line between Songdo and Incheon, the Turkish
Marmaray project
The Marmaray () is a intercontinental commuter rail line in Istanbul, Turkey. A rail tunnel running under the Bosphorus strait was connected to an upgraded version of the old suburban train service (known as the banliyö), allowing trains ...
, and the
London Overgound's
East London line, as well as on viaducts in urban areas. LVT has become the standard ballastless-track system in Switzerland.
IVES
The IVES system (''Intelligent, Versatile, Efficient and Solid'') is a product of Rhomberg Rail. The system consists of a base layer (preferably common asphalt concrete) and concrete lateral structural elements, in which the rail fastening elements of the type DFF 304 are directly embedded – no ties/sleepers are needed. The necessary elasticity is given only by a flexible intermediate plate in the rail fastening elements.
The structural elements of this system are individually manufactured and can be positioned laterally or longitudinally onto the base layer. The structural elements have recesses in the top, where the rail fastening elements are placed into. Afterwards, the rails are lifted onto the fastening elements and a track grid is established. The grid’s exact position can now be adjusted vertically and laterally. At last, the rail fastening elements are friction-locked to the structural elements with high-strength grouting mortar. Thanks to its versatile construction and easy installation, IVES is suitable for all rail types.
After testing, the first IVES track has been installed in the Asfordby Tunnel of the
Old Dalby Test Track
The Old Dalby Test Track is a railway in the United Kingdom which is used for testing new designs of trains and railway infrastructure. It runs between Melton Mowbray, Leicestershire and Edwalton, on the course of the Midland Railway's route betw ...
in England in 2013 and since then, 7 more IVES tracks have been built. The longest IVES track runs through the Bruggwaldtunnel in Switzerland, with a total length of 1,731 m.
See also
Baulk track and
slab track
A ballastless track or slab track is a type of railway track infrastructure in which the traditional elastic combination of ties/sleepers and ballast is replaced by a rigid construction of concrete or asphalt.
Characteristics
In ballastless ...
are similar in that the rails are continuously supported, compared to ordinary track where the rails have to "bridge" the gaps between the sleepers.
References
{{Authority control
Railway line types
Railway track layouts