Ladder track
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Ladder track is a type of
railway track Railway track ( and UIC terminology) or railroad track (), also known as permanent way () or "P way" ( and Indian English), is the structure on a railway or railroad consisting of the rails, fasteners, sleepers ( railroad ties in American ...
in which the track is laid on
longitudinal Longitudinal is a geometric term of location which may refer to: * Longitude ** Line of longitude, also called a meridian * Longitudinal engine, an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, ...
supports with
transverse Transverse may refer to: *Transverse engine, an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle *Transverse flute, a flute that is held horizontally * Transverse force (or ''Euler force''), the tangen ...
connectors holding the two rails at the correct
gauge Gauge ( ) may refer to: Measurement * Gauge (instrument), any of a variety of measuring instruments * Gauge (firearms) * Wire gauge, a measure of the size of a wire ** American wire gauge, a common measure of nonferrous wire diameter, especia ...
distance. Modern ladder track can be considered a development of
baulk road 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 int ...
, which supported rails on longitudinal wooden sleepers. Synonyms include longitudinal beam track.


History and overview

Ladder type track has also been used historically on bridges lacking ballast, and in situations requiring good drainage or ease of maintenance such as stations. Described as track with longitudinal bearers with cross ties, ladder track type was common on early British railways (c.1830/40s), including the
Birmingham and Gloucester Railway The Birmingham and Gloucester Railway (B&GR) was the first name of the railway linking the cities in its name and of the company which pioneered and developed it; the line opened in stages in 1840, using a terminus at Camp Hill railway station, ...
,
Dublin and Kingstown Railway The Dublin and Kingstown Railway (D&KR), which opened in 1834, was Ireland's first passenger railway. It linked Westland Row in Dublin with Kingstown Harbour (Dún Laoghaire) in County Dublin. The D&KR was also notable for a number of other a ...
,
Glasgow, Paisley, Kilmarnock and Ayr Railway The Glasgow, Paisley, Kilmarnock and Ayr Railway (GPK&AR) was a railway in Scotland that provided train services between Glasgow, Kilmarnock and Ayr. It opened its first line, between Glasgow and Ayr, in stages from 1839 to 1840. The section b ...
,
Great Western Railway The Great Western Railway (GWR) was a History of rail transport in Great Britain, British railway company that linked London with the southwest, west and West Midlands (region), West Midlands of England and most of Wales. It was founded in 1833, ...
(see
Baulk road 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 int ...
),
Ulster Railway The Ulster Railway was a railway company operating in Ulster, Ireland. The company was incorporated in 1836 and merged with two other railway companies in 1876 to form the Great Northern Railway (Ireland). History The Ulster Railway was au ...
, Newcastle and North Shields Railway,
Slamannan Railway The Slamannan Railway was an early mineral railway between the north-eastern margin of Airdrie, North Lanarkshire, Airdrie and Causewayend on the Union Canal (Scotland), Union Canal, near Linlithgow, Scotland. The Slamannan Railway was built to ...
(part of),
Hull and Selby Railway The Hull and Selby Railway is a railway line between Kingston upon Hull and Selby in the United Kingdom which was authorised by an act of Parliament in 1836 and opened in 1840. As built the line connected with the Leeds and Selby Railway (opened ...
(two thirds of), Manchester and Bolton Railway (including lontudinal stone sleepers), and the
London and Greenwich Railway The London and Greenwich Railway (L&GR) was opened in London between 1836 and 1838. It was the first steam railway in the capital, the first to be built specifically for passengers, and the first entirely elevated railway. Origins The idea for ...
(partly). On the Hull and Selby Railway it was used in part as it was noted to produce smooth running, and low wheel wear. However the contact between rail and sleeper produced hydraulic pumping in wet conditions, which led to rolling stock becoming dirtied very quickly. The longitudinal track was also found to cause issue with wheel slip on inclines, and to be noticeably inferior to transverse sleepered track in terms of traction. No longitudinally laid track remained on the line after 1860. Research into longitudinal sleepers took place in Japan, Russia and France in the mid 20th century. In the late 20th century, interest in ladder type tracks increased due to its potential for lower cost and lower maintenance railways, as well as increased stability benefits over sleepered track. In general, ladder track produces lower pressures on the road bed: both the maximum pressure and the amplitude of pressure pulses are smaller than transverse sleepered track, which can reduce maintenance costs in ballasted systems. An additional benefit in ballasted ladder track is increased resistance to ballast wash out and other forms of ballast degradation due to the additional longitudinal support and rigidity in ladder track; the same structural rigidity also adds to buckling resistance.


Design variants


Tubular Modular Track

Tubular Modular Track (TMT) is a type of ballastless ladder track manufactured by Tubular Track (Pty.) Ltd. of South Africa first introduced in 1989.Company Profile : Tubular Track
''www.tubulartrack.co.za''
and invented by Peter Küsel. The track consists of steel rail resting on concrete supports via rubberised cork absorption pads with galvanised steel tie beams which wrap around the concrete members rather than being cast into the concrete as with other ladder tracks. The track is modular and precast, rather than being cast in situ. Modular turnouts are also produced. The modular nature and controlled production of the track sections has the advantage of rapid installation and good quality control. The ballastless and modular nature of the track makes it advantageous for both wet and desert conditions where ballast degradation is problematic, as well as in mines where transportation of the track components is simplified. Since the rail is continuously supported rail stresses are less; a 34 tonne axle load version has been designed and lighter rails can be used compared to sleepered track, additionally maintenance costs of ballast are reduced. The track has been used mainly in southern Africa, including a section of the
Gautrain Gautrain is an Higher-speed rail, higher-speed Express train, express commuter rail system in Gauteng, South Africa, which links Johannesburg, Pretoria, Kempton Park, Gauteng, Kempton Park and O. R. Tambo International Airport. It takes 15 minu ...
line in South Africa. The system has also been used in Saudi Arabia.


RTRI Japan ladder tracks

The Railway Technical Research Institute of Japan has developed two types of ladder track; ballasted and a floating un-ballasted type. Both types utilise a 'combined rail' of steel rails each attached through a conventional modern railway fastener to a longitudinal pre-stressed concrete supports (6.25m long) which are kept in gauge by thick walled tubular steel cross members embedded in the concrete. Forms for axle load of 40 tonnes have been designed. The ballasted track show reduced maintenance (tamping) compared to conventional cross-tie sleeper track, longitudinal creep is greater than that in conventional track; for this reason transverse 'anti creep' panels are included in the structure. The non-ballasted track is supported by vibration absorbing springs (or elastomeric pads) on a concrete road bed; the combined structure shows reduced vertical vibrations of the track bed compared to conventional track This property gives reduced noise levels when the track is utilised in a steel girder bridge.


Other types

Specialised Track Systems (Pty.) Ltd. licenses its technology for ladder track to contractors; the track system is ballastless with steel lateral braces in a concrete roadbed, support of the track is by conventional
rail fastening system A rail fastening system is a means of fixing Rail profile, rails to railroad ties (North America) or sleepers (British Isles, Australasia, and Africa). The terms ''rail anchors'', ''tie plates'', ''chairs'' and ''track fasteners'' are used to r ...
s spaced at regular intervals. The design can also incorporate ducts within the beams (for cabling) and can be converted to slab track by in-situ concrete pouring. The company's main market is mining applications.Specialised Track Systems
Company website , ''www.track.co.za''


See also

*
Railroad tie A railroad tie, crosstie (American English), railway tie (Canadian English) or railway sleeper ( Australian and British English) is a rectangular support for the rails in railroad tracks. Generally laid perpendicular to the rails, ties trans ...
* Trackless train


References

{{Rail tracks Permanent way