Ballastless track

Last updated

Slab track with flexible noise-reducing rail fixings, built by German company Max Bogl, on the Nurnberg-Ingolstadt high-speed line Feste Fahrbahn FFBogl.jpg
Slab track with flexible noise-reducing rail fixings, built by German company Max Bögl, on the Nürnberg–Ingolstadt high-speed line

A ballastless track or slab track is a type of railway track infrastructure in which the traditional elastic combination of sleepers and ballast is replaced by a rigid construction of concrete or asphalt. It is considered the standard for high-speed and heavy haul railway lines. [1] It is also commonly used for urban tramways. [2]

Contents

Ballastless track of the type "Low Vibration Track" in a turnout in the Gotthard Base Tunnel's Faido multifunction station 20141120 gotthard-basistunnel02-wikipedia-hannes-ortlieb.jpg
Ballastless track of the type "Low Vibration Track" in a turnout in the Gotthard Base Tunnel's Faido multifunction station

Characteristics

In ballastless tracks, the rails are either discretely supported or continuously supported. Discretely supported rails sit on elastomeric pads and are rigidly fastened to special types of concrete sleepers. These sleepers are themselves set directly in concrete or in rubber 'boots' and both are then set in concrete. Continuously supported rails are generally fixed in slots in the concrete slab and called Embedded Rail Track. The rails, which can be either traditional Vignole Rails with a head, web and foot, or block rails with no web, are either cast into the slots by an elastic compound or surrounded by a close-fitting boot before being fixed in place with grout. Both the surface mounted rail and the embedded block rail can be simply removed and replaced.

Ballastless tracks offer a high consistency in track geometry which is difficult to adjust after the concreting of the superstructure; they must therefore be concreted with a tolerance of ± 1.0 mm. [3]

The elasticity of the ballast in the traditional railway superstructure is replaced by flexibility between either the discretely supported rails and the concrete sleepers, or the sleepers and the concrete or asphalt slab (e.g., with sleeper boots). The slab itself is relatively inelastic. [3]

Special care is needed for the design of transitions zones between conventional and ballastless track, for example near bridges. [4]

Advantages

The advantages of a ballastless track over a traditional superstructure are its highly consistent track geometry, its longer life span of up to 100 years, and the reduced need for maintenance. [5] [6]

A ballastless track's track geometry is achieved mainly due to its relative inelasticity in comparison to a traditional superstructure. This results in far fewer deformations and generally smoother running; train drivers of the London Overground's East London Line have opined that the Low Vibration Track system is the smoothest superstructure they have experienced. [7] Measurements conducted in Switzerland in 2003 and 2004 showed a standard deviation of the gauge of less than 1.2 millimetres (0.047 in). [6] This in turn increases the track's life span and reduces the need for maintenance. The usual preventive maintenance is limited to rail grinding and, in the case of surface mounted rail, inspection of the rail fixings, since tamping is not necessary due to the absence of ballast. Curative maintenance beyond rail and fixing replacement is required only after several decades. The Swiss Federal Railways replaced the sleepers and rubber shoes of the ballastless track in the 4.9-kilometre (3.0 mi)-long Heitersberg Tunnel between 2014 and 2016, whereas no maintenance of the concrete slab was necessary 39 years after the tunnel's opening. [8] [9]

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 viaducts. [9] Elsewhere ballastless track is used in the open.

Further advantages of ballastless tracks include better and controlled drainage, the elimination of flying-ballast damage on rolling stock and civil engineering structures, a shallower superstructure, and the possibility of run-over sections such as crossings or shared tram-bus lanes over which pneumatic vehicles can be driven. When used in stations, ballastless tracks are easier to clean. [9] [2]

Embedded track has the potential for increased safety through simple derailment protection and support of broken rails. They alone can also be installed by the efficient placing of the slab using the slipform process. All these benefits lead to increased track access for the traffic.

Disadvantages

The primary disadvantage of a ballastless track is its sometimes 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 estimated in 2015 that construction costs of ballastless tracks are in many cases 28 percent higher than those of traditional superstructure. [10] ] However, the life-cycle cost of ballastless tracks are generally lower than those of ballasted tracks due to significantly lower maintenance. [11]

Further disadvantages of ballastless tracks are the difficulty of adjusting or correcting track geometry once concrete has been set, the necessity of a stable infrastructure (since adjustments to the superstructure can be onerous), generally higher noise emissions, and longer and more expensive repairs when the concrete slab is damaged (for e.g., due to construction faults, wear and tear, or accidents). Inflexibility of the track and the need to be careful with transitions between ballasted and ballastless tracks have been cited as well. [12] [13]

Construction types

Early slab track projects a range of construction types, sub-bases and fastening technologies. [14] The following list contains construction types of ballastless tracks that have been internationally used in heavy-rail systems (as opposed to light railways, tramways, or metros) in chronological order of their first usage. [12] [15]

Classification of ballastless track systems [13]
TypeSubtypeExample
Discrete rail supportSleepers encased in concreteRheda 2000
Sleepers on top of bedATD, GETRAC
Prefabricated concrete slabsBögl
Monolithic Lawn track
Continuous rail supportEmbedded rail structureDeck track
Continuously supported rail

Rheda 2000

RHEDA 2000 - 02.JPG
Rheda 2000 before pouring
RHEDA 2000 - 12.JPG
Rheda 2000 after pouring

One of the first applications of ballastless track was in Rheda, Germany, where it was constructed in 1972. [5] This developed into the Rheda 2000 system, first used on the Erfurt–Leipzig/Halle high-speed railway. [16] This system uses sleepers or blocks encased in concrete, poured in-situ. [13] [17]

ATD

ATD is the abbreviation for Asphalt Supporting layer for Track Direct support. Its characteristics include rails connected to along rail axis connected sleepers made from dual-block concrete installed onto a supporting layer of asphalt. It has been applied to tramways. [18] [19]

SBB Bözberg/STEDEF (SBB)

The Bözberg/STEDEF system consists of twin 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. [9] STEDEF was further developed by SATEBA prior to the system's installation on the French LGV Méditeranée. [20]

Bögl (Max Bögl)

Bogl ballastless track, on the Nuremberg-Ingolstadt high-speed railway Feste Fahrbahn FFBogl.jpg
Bögl ballastless track, on the Nuremberg–Ingolstadt high-speed railway

The Bögl ballastless track is characterised by its use of prefabricated 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 and Heidelberg in 1999. For its use on the high-speed link between Beijing and Shanghai, 406,000 slabs were installed. [21]

FF ÖBB/PORR (PORR)

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, [22] 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 system will be used on the first phases of the United Kingdom's High Speed 2 line, except in tunnels and for some specialist structures. [23] It is also being used for the Delhi-Meerut RRTS, the first of 3 RRTS systems currently being implemented in Delhi-NCR by NCRTC. [24]

Ballastless track of the type "Low Vibration Track" in the Gotthard Base Tunnel's Sedrun multifunction station Porta Alpina.jpg
Ballastless track of the type "Low Vibration Track" in the Gotthard Base Tunnel's Sedrun multifunction station

Low Vibration Track (Sonneville/Vigier Rail)

The Low Vibration Track (LVT) system is similar to Bözberg/STEDEF in that it also uses twin sleepers enclosed in rubber shoes. [9] [25] However, LVT does not feature a tie rod. [9] The system was developed and tested by Roger Sonneville together with the Swiss Federal Railways in the 1990s [3] before the rights were sold to Vigier Rail in 2009. [26] LVT has been in service in the Channel tunnel 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, Gotthard and Ceneri base tunnels, the South Korean high-speed Suin Line between Songdo and Incheon, the Turkish Marmaray project, and the London Overground's East London line, as well as on viaducts in urban areas. [27] [28] LVT has become the standard ballastless-track system in Switzerland. [29]

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 [30] are directly embedded – no 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. [31]

After testing, the first IVES track has been installed in the Asfordby Tunnel of the Old Dalby Test Track in England in 2013 [32] and since then, seven more IVES tracks have been built. The longest IVES track runs through the Bruggwaldtunnel in Switzerland, with a total length of 1,731 m (5,679 ft). [33]

Deck track

Deck track consists of an endless concrete beam which is buried in the ground with the track fixed directly on top of it. The concrete beam is made hollow to match the soil density. Due to the large diameter of the hollow beam and its light weight, it is particularly suitable for low profile designs on soft soils. Deck track has been implemented on small sections of the Havenspoorlijn Rotterdam  [ nl ], which is part of the Betuweroute. [34] [35]

See also

Related Research Articles

<span class="mw-page-title-main">Railway track</span> Rail infrastructure

A railway track or railroad track (NAmE), also known as permanent way (CwthE) or "P Way", is the structure on a railway or railroad consisting of the rails, fasteners, sleepers and ballast, plus the underlying subgrade. It enables trains to move by providing a dependable, low-friction surface on which their wheels can roll. Early tracks were constructed with wooden or cast-iron rails, and wooden or stone sleepers. Since the 1870s, rails have almost universally been made from steel.

<span class="mw-page-title-main">History of the railway track</span>

The railway track or permanent way is the elements of railway lines: generally the pairs of rails typically laid on the sleepers or ties embedded in ballast, intended to carry the ordinary trains of a railway. It is described as a permanent way because, in the earlier days of railway construction, contractors often laid a temporary track to transport spoil and materials about the site; when this work was substantially completed, the temporary track was taken up and the permanent way installed.

<span class="mw-page-title-main">Railroad tie</span> Support for the rails in railroad tracks

A railroad tie, crosstie, railway tie or railway sleeper is a rectangular support for the rails in railroad tracks. Generally laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade, hold the rails upright and keep them spaced to the correct gauge.

<span class="mw-page-title-main">Railgrinder</span> Railway maintenance vehicle

A railgrinder is a maintenance of way vehicle or train used to restore the profile and remove irregularities from worn tracks to extend its life and to improve the ride of trains using the track. Rail grinders were developed to increase the lifespan of the tracks being serviced for rail corrugation. Rail grinding is a process that is done to stop the deformation due to use and friction on railroad tracks by removing deformations and corrosion. Railway tracks that experience continual use are more likely to experience corrugation and overall wear. Rail grinders are used to grind the tracks when rail corrugation is present, or before corrugation begins to form on the tracks. Major freight train tracks use rail grinders for track maintenance based on the interval of tonnage, rather than time. Transit systems and subways in major cities continue to use scheduled rail grinding processes to combat the corrugation common to heavily used tracks. Rail-grinding equipment may be mounted on a single self-propelled vehicle or on a dedicated rail-grinding train which, when used on an extensive network, may include crew quarters. The grinding wheels, of which there may be more than 100, are set at controlled angles to restore the track to its correct profile.

<span class="mw-page-title-main">Maintenance of way</span> Aspect of rail transport operations

Maintenance of way refers to the maintenance, construction, and improvement of rail infrastructure, including tracks, ballast, grade, and lineside infrastructure such as signals and signs.

<span class="mw-page-title-main">Track ballast</span> Trackbed upon which railway ties are laid

Track ballast is the material which forms the trackbed upon which railroad ties are laid. It is packed between, below, and around the ties. It is used to bear the compression load of the railroad ties, rails, and rolling stock; to facilitate drainage; and keep down vegetation that can compromise the integrity of the combined track structure. Ballast also physically holds the track in place as the trains roll over it. Not all types of railway tracks use ballast.

High-speed railway track construction is the process by which Lignes à Grande Vitesse, the land on which TGV trains are to run, is prepared for their use, involving carving the track bed and laying the track. This construction technique is used both for the French TGV network and other TGV-based networks outside of France.

<span class="mw-page-title-main">Pandrol</span> Rail fastener manufacturer

Pandrol is a global railway infrastructure equipment and technology company. It is presently a member of the Delachaux Group and based in Colombes, France and has 1,700 employees globally in over 40 locations. Pandrol has sold its various products to over 400 railway systems around the world.

<span class="mw-page-title-main">Tamping machine</span> Type of railroad maintenance vehicle

A tamping machine or ballast tamper, informally simply a tamper, is a self-propelled, rail-mounted machine used to pack the track ballast under railway tracks to make the tracks and roadbed more durable and level. Prior to the introduction of mechanical tampers, this task was done by manual labour with the help of beaters. As well as being faster, more accurate, more efficient and less labour-intensive, tamping machines are essential for the use of concrete sleepers since they are too heavy to be lifted by hand.

<span class="mw-page-title-main">Work train</span> Rail infrastructure maintenance unit

A work train is one or more rail cars intended for internal non-revenue use by the railroad's operator. Work trains serve functions such as track maintenance, maintenance of way, revenue collection, system cleanup and waste removal, heavy duty hauling, and crew member transport.

<span class="mw-page-title-main">Concrete sleeper</span> Railway sleeper made out of prestressed concrete

A concrete sleeper or concrete tie is a type of railway sleeper or railroad tie made out of steel reinforced concrete.

<span class="mw-page-title-main">Deck (bridge)</span> Surface of a bridge

A deck is the surface of a bridge. A structural element of its superstructure, it may be constructed of concrete, steel, open grating, or wood. Sometimes the deck is covered by a railroad bed and track, asphalt concrete, or other form of pavement for ease of vehicle crossing. A concrete deck may be an integral part of the bridge structure or it may be supported with I-beams or steel girders.

<span class="mw-page-title-main">Rail fastening system</span> Rail-tie/sleeper binding mechanism

A rail fastening system is a means of fixing rails to railroad ties or sleepers. The terms rail anchors, tie plates, chairs and track fasteners are used to refer to parts or all of a rail fastening system. The components of a rail fastening system may also be known collectively as other track material, or OTM for short. Various types of fastening have been used over the years.

<span class="mw-page-title-main">Baulk road</span> Railway track on undergirding timber bearings

Baulk road is the name given to a type of railway track or 'rail road' that is formed using rails carried on continuous timber bearings, as opposed to the more familiar 'cross-sleeper' track that uses closely spaced sleepers or ties to give intermittent support to stronger rails.

The Research Designs & Standards Organisation (RDSO) is the research and development and railway technical specification development organisation under the Ministry of Railways of the Government of India, which functions as a technical adviser and consultant to the Railway Board, the Zonal Railways, the Railway Production Units, RITES, RailTel and Ircon International in respect of design and standardization of railway equipment and problems related to railway construction, operations and maintenance.

Ladder track is a type of railway track in which the track is laid on longitudinal supports with transverse connectors holding the two rails at the correct gauge distance. Modern ladder track can be considered a development of baulk road, which supported rails on longitudinal wooden sleepers. Synonyms include longitudinal beam track.

<span class="mw-page-title-main">Calamba station</span> Railway station in Laguna, Philippines

Calamba station is a railway station located on the South Main Line in Laguna, Philippines. It is one of two railway stations in the city and it is a major station on the line, serving as the junction between the South Main Line and the old Calamba–Batangas branch line which used to connect to Batangas City. It is also envisioned to be the terminus of the Commuter Express when rehabilitation work is complete. The station was first opened on January 24, 1909.

<span class="mw-page-title-main">Track renewal train</span> Rail and sleeper replacement machine

A track renewal train is a work train that consists of many units of machinery and materials required for track renewal projects.

<span class="mw-page-title-main">Bözberg Rail Tunnel</span> Railway tunnel in the Swiss canton of Aargau

The Bözberg Rail Tunnel is a railway tunnel in the Swiss canton of Aargau. It takes the Bözberg railway line of the Swiss Federal Railways under the Bözberg Pass between Effingen and Schinznach-Dorf. The original tunnel was opened during 1875; it is set to be closed to rail traffic during 2020-2021 following the commissioning of its replacement, after which it shall be converted and retained for service and rescue purposes in respect to its successor.

The Glenbrook Tunnel is a double-track railway tunnel located on the Main Western Line, near Glenbrook, in the City of Blue Mountains local government area of New South Wales, Australia. The property is owned by the Transport Asset Holding Entity. The railway tunnel is part of the Glenbrook 1913 double-track deviation, which replaced the Glenbrook 1892 single-track deviation across the Blue Mountains. The tunnel is 283 metres (928 ft) long and was officially opened on 11 May 1913.

References

  1. ↑ Freudenstein, Stephan (August 2010). "RHEDA 2000 ® : ballastless track systems for high-speed rail applications". International Journal of Pavement Engineering. 11 (4): 293–300. doi:10.1080/10298431003749774. ISSN   1029-8436.
  2. 1 2 "TRAMBANEN IN BETON" (PDF). April 2017.
  3. 1 2 3 "Precision laying of low-maintenance track". Railway Gazette International: 44f. July 2011.
  4. ↑ Lund, Henrik; Åswärdh, Andreas. "Transition zones between ballasted and ballastless track".
  5. 1 2 Batreak, Oleksandr (14 April 2021). "High speed without ballast". Railway Supply. Archived from the original on 18 May 2021. Retrieved 4 February 2025.
  6. 1 2 Rutishauser, Gérard (2005). Slab Track "Swiss Made": 40 Years Successful Experience. European Slab Track Symposium 2005. pp. 3, 10.
  7. ↑ Whitelaw, Jackie (27 May 2010). "East London Line: Southern Section". New Civil Engineer . p. 38.
  8. ↑ "S-Bahn- und Fernverkehr Zürich–Olten: SBB saniert Fahrbahn im Heitersbergtunnel | SBB". www.sbb.ch (in German). 18 December 2013. Archived from the original on 1 October 2017. Retrieved 17 September 2017.
  9. 1 2 3 4 5 6 "Gotthard Base Tunnel completes LVT installation". Railway Gazette International: 40f., 43. January 2015.
  10. ↑ Zippel, Tino (17 June 2015). "Pünktlicher Start für ICE-Neubaustrecke: Deutsche Bahn arbeitet an Plan B". Ostthüringer Zeitung (in German). Archived from the original on 17 December 2015. Retrieved 17 September 2017.
  11. ↑ Awasthi, Anupam (28 November 2020). "Slab Track System for High Speed Railway". nhsrcl.in. NHSRCL. Retrieved 3 January 2023. From Japanese experience, it has been learnt that although initial construction cost of slab track is about 1.3 times higher compared to conventional ballasted track, if we consider life cycle cost in the long run, slab track seems to win the race.
  12. 1 2 Esveld, Coenraad (2001). Modern Railway Track (PDF). The Netherlands: MRT-Productions. p. 233. ISBN   90-800324-3-3.
  13. 1 2 3 Serdelová, Katarína; Vičan, Josef (1 January 2015). "Analysis and Design of Steel Bridges with Ballastless Track". Procedia Engineering. XXIV R-S-P seminar, Theoretical Foundation of Civil Engineering (24RSP) (TFoCE 2015). 111: 702–708. doi:10.1016/j.proeng.2015.07.135. ISSN   1877-7058.
  14. ↑ "Technical and Economic Feasibility Study of At-Grade Concrete Slab Track for Urban Transit Systems" (PDF). 1981. Retrieved 16 November 2019.
  15. ↑ Michas, Georgios (2012). Slab Track Systems for High-Speed Railways (Master Degree Project) (PDF) (Technical report). Royal Institute of Technology, Stockholm, Sweden. TSC-MT 12-005.
  16. ↑ Bachmann, H.; Mohr, W.; Kowalski, M. (2003). "The Rheda 2000 Ballastless Track System". European Railway Review (1). ISSN   1351-1599.
  17. ↑ Bachmann, H.; Freudenstein, S. (2004). "Low-Cost Track Systems Rheda 2000 and Getrac A3". European Railway Review. 10 (3). ISSN   1351-1599.
  18. ↑ "ATD-G and Rheda City Green the Tracks for Urban Transit" (PDF).
  19. ↑ Jadidi, Kazem; Esmaeili, Morteza; Kalantari, Mehdi; Khalili, Mehdi; Karakouzian, Moses (31 December 2020). "A Review of Different Aspects of Applying Asphalt and Bituminous Mixes under a Railway Track". Materials. 14 (1): 169. doi: 10.3390/ma14010169 . ISSN   1996-1944. PMC   7795125 . PMID   33396501.
  20. ↑ "Système de voie sans ballast". Consolis SATEBA (in French). 2012. Retrieved 17 September 2017.
  21. ↑ Firmengruppe Max Bögl: "Hochgeschwindigkeit in China mit FF Bögl" MB Quadrat (in German). 2010. pp. 18f.
  22. ↑ "Slab Track Austria: System ÖBB-PORR elastically supported slab (sic)" (PDF). Slab Track Austria. 2012. p. 2.
  23. ↑ "HS2 slab track contract awarded". Railway Gazette International . 5 October 2020. Archived from the original on 7 October 2020. Retrieved 7 October 2020.
  24. ↑ "In-principle approval of broad technologies for regional rapid transit system (RRTS)" (PDF). indianrailways.gov.in. Ministry of Railways. 18 November 2020. p. 1. Retrieved 3 January 2024. NCRTC has selected "Austrian Slab Track System" for track on main line.
  25. ↑ Carr, Collin (May 2014). "Canal Tunnels: Exercising Foresight". The Rail Engineer: 30.
  26. ↑ Sonneville AG (2017). "History". www.sonneville.com. Retrieved 23 September 2017.
  27. ↑ Sonneville AG (July 2015). "LVT Reference List - Metric Version" (PDF). www.sonneville.com. Retrieved 23 September 2017.
  28. ↑ Sonneville AG (2017). "LVT on Viaducts". www.sonneville.com. Retrieved 23 September 2017.
  29. ↑ Rubi, Thomas; Gerber, Tobias; Trovato, Marco; Hengelmann, Anabel; Laborenz, Peter; Ziegler, Armin (August 2012). "Keeping it Quiet Below the Streets of Zürich". Railway Gazette International: 44–7.
  30. ↑ AG, Vossloh. "System DFF 304". www.vossloh.com (in German). Archived from the original on 30 April 2019. Retrieved 7 June 2019.
  31. ↑ Rhomberg Rail. "Documentation Slab Track IVES" (PDF). Retrieved 1 June 2019.
  32. ↑ Rhomberg Rail. "References IVES" (PDF). Retrieved 7 June 2019.
  33. ↑ "Von der Tradition zur Moderne". Schriftzug (in Swiss High German). 26 February 2019. Retrieved 7 June 2019.
  34. ↑ Bos, J. A.; Stuit, H. G. (2000). "Deck track: new philosophy of track building". Proceedings of the International Conference, Railway Engineering 2000, Held London, UK, July 2000 - CD-ROM.
  35. ↑ Aly, Mohamed Ismail; El-Shabrawy, Mohamed; El Gendy, Mohamed; Adel Turk, Ahmed (25 January 2018). "Analysis of Ballastless Railway Track Structures Over Soft Clays". Malaysian Journal of Civil Engineering. 29 (2). doi:10.11113/mjce.v29.15595. ISSN   2600-9498.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.