Ballast tamper
Encyclopedia
Tamp
A tamp is a device used to compact or flatten an aggregate or other powdered or granular material, typically to make it resistant to further compression or simply to increase density....
) the track ballast
Track ballast
Track ballast forms the trackbed upon which railway sleepers or railroad ties are laid. It is packed between, below, and around the ties. It is used to facilitate drainage of water, to distribute the load from the railroad ties, and also to keep down vegetation that might interfere with the track...
under railway tracks to make the tracks more durable. Prior to the introduction of mechanical tampers, this task was done by manual labour
Manual labour
Manual labour , manual or manual work is physical work done by people, most especially in contrast to that done by machines, and also to that done by working animals...
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
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
sleeper
Railroad tie
A railroad tie/railway tie , or railway sleeper is a rectangular item used to support the rails in railroad tracks...
s since they are too heavy (usually over 250 kg (551 lb)) to be packed into the ballast by hand.
Early machines only lifted the track and packed the ballast. More modern machines, sometimes known as a tamper-liner or tamping and lining machine, also correct the alignment of the rails to make them parallel and level, in order to achieve a more comfortable ride for passengers and freight and to reduce the mechanical strain applied to the rails by passing trains.
Functions of tamping machines
- Packing of ballast under sleepers
- Correction of cross levelCross levelCross level is the height difference between the left rail and the right rail in a railway track. If this level is not zero in a straight track passenger riding will not be comfortable with jerks either to left or right...
- Correction of Longitudinal Level
- Driving
- Run Drive
- Work Drive
- Special Functions
- Twist Corrections
- Track Settlement
- Laser Lining
- Automatic Data Feeding by Computer
- Recording of Track Parameter
Types
Ballast Tampers are built in many different varieties depending on their purpose:Tamping machines
- Straight track tamping machines:
- Universal tamping machines (U.T.)
- Unomatic
- Duomatic
- Continuous action tamping machines (C.S.M.)
- Tamping Express
- Points and crossing tamping machines (UNIMAT )
- Multi-purpose tamping machines (M.P.T.)
Non-tamping machines
- DTS (DGS), Dynamic Track Stabilizing Machine
- Points And Crossing Relaying Machine (P&C T-28)
- Track Relaying Train (T.R.T.)
- Straight Track Laying Machines (P.Q.R.S.)
General arrangement
The majority of track machines are powered by a diesel engineDiesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
. This provides power to the driving wheels via a cardan shaft
Driveshaft
A drive shaft, driveshaft, driving shaft, propeller shaft, or Cardan shaft is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement...
, allowing the machine to propel itself to and around a work-site. The engine also drives an hydraulic pump to provide power for the various tools.
Tamping units
Hydraulic cylinder
A Hydraulic cylinder is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in engineering vehicles.- Operation :...
. The tamping unit consists of tamping tools (arms or "tines"), a vibration motor (hydraulic motor
Hydraulic motor
A hydraulic motor is a mechanical actuator that converts hydraulic pressure and flow into torque and angular displacement . The hydraulic motor is the rotary counterpart of the hydraulic cylinder....
), a vibration shaft and an eccentric
Eccentric (mechanism)
In mechanical engineering, an eccentric is a circular disk solidly fixed to a rotating axle with its centre offset from that of the axle ....
flywheel
Flywheel
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...
. For each sleeper, a tamping unit is provided with four pairs of tamping arms: one each side of the sleeper, i.e., 16 tamping arms are used for tamping a single sleeper. To process several sleepers simultaneously, a tamping unit may have 32 arms (for two sleepers), leading to the derivation of machine type numbers: "16" indicates 16 tines, enough for single sleeper, "32" for two sleepers, etc.
Tamping units of a Unimat have swivelling tamping arms to pack points and crossings.
Special units are available for use with third-rail electrified track.
Universal tamping machine
This type of straight-track tamping machine is the oldest of the varieties. It uses a two-chord lining system for alignment of track (for slewing the track to left or right, as-and-when required). This type of lining is controlled mechanically. The machine has four bogieBogie
A bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage/car or locomotive, or sprung as in the suspension of a caterpillar...
s, one at the front, one at the rear, a third in the centre and a fourth in between the centre and the rear. They are called: front-tightening, rear-tightening, lining bogie and measuring bogie, respectively.
The measuring bogie determines the amount of slewing required and measures the subsequent adjustments applied by the lining bogie. The lining bogie also lifts the track to make it level. The tamping bank behind the lining bogie has a vibrating motor and four arms for each rail.
A tamping cycle comprises three operations:
- Penetration – the arms are pushed down vertically into the ballast either side of a sleeper
- Squeezing – the arms squeeze the ballast under the sleeper, packing it together
- Moving – the arms are lifted and the machine is moved to the next sleeper to repeat the cycle.
The operations are controlled from the control cabin by an operator using three pedals, while the lining bogie holds the track in its lifted and slewed position.
CSM
A Continuous Tamping Machine (CSM) can pack two sleepers at a time in a continuous mode and can pack (tamp) about 1.2 km of track per hour.BCM
A Ballast Cleaning Machine (BCM) carries-out deep screening of ballast, which is an important maintenance activity to improve drainageDrainage
Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to improve production or to manage water supplies.-Early history:...
and the resilience of the track. The cutter blades of the BCM dig out ballast from under and around the sleepers, and a conveyor belt
Conveyor belt
A conveyor belt consists of two or more pulleys, with a continuous loop of material - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley...
transfers it to the on-board cleaning equipment where the ballast is passed over screens which remove fine debris. The clean screened ballast is returned to the track and the fine screened residue is ejected to one side, usually into a hopper wagon on an adjacent track.
A BCM can deep-screen 650 cubic metres of ballast per hour of working, and proceed at up to two miles an hour, but must be followed by a tamper/liner to restore the correct track geometry.
DGS / DTS (Dynamic Track Stabilising)
Tamping and cleaning operations have the adverse effect of reducing the resistance of the track to lateral movement. The resistance gradually recovers with the passage of trains, but may require a speed restriction imposed for the duration. This 'consolidation' can be achieved faster and in a more controlled manner using mechanised equipment known as the Dynamic Track Stabiliser (DTS).A DTS will normally be used only after a stretch of track has been tamped and aligned.
D.G.S. has a vibrating unit which holds the track in position and applies a vertical vibration to simulate the passage of trains. The track parameters (or cross levels), before and after stabilising, can be viewed through bogies in the front and rear.
Dynamic Track Stabilising has the following advantages, resulting in enhanced safety:
- Increases the resistance of the track to lateral movement;
- Creates a homegenous bed of ballast;
- Permits earlier relaxation of speed restrictions;
- Eliminates non-uniform initial differential settlements caused by rail traffic;
- Retains correct track geometry for a longer period than was achievable using tamping machines alone.
- Vibration frequency: 30–35 Hz
- Working speed: 1–2 km/h
- Vertical pressure applied: 100 kg/cm²
The stabilisation achieved by one pass of a D.G.S. is equal to that achieved by 100,000 tonnes of traffic, and allows a speed restriction of 20 km/h to be relaxed to 40 km/h
Dynamic stabilisation is usually avoided on bridges or around overhead structures since there is a risk of damage to foundations.
Gallery
File:IMG 2067 Railway works vehicles.jpg|A picture of a Polish
Poles
thumb|right|180px|The state flag of [[Poland]] as used by Polish government and diplomatic authoritiesThe Polish people, or Poles , are a nation indigenous to Poland. They are united by the Polish language, which belongs to the historical Lechitic subgroup of West Slavic languages of Central Europe...
ballast tamper/track tamper .
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French people
The French are a nation that share a common French culture and speak the French language as a mother tongue. Historically, the French population are descended from peoples of Celtic, Latin and Germanic origin, and are today a mixture of several ethnic groups...
ballast tamper /track tamper .
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Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....
ballast tamper /track tamper .
File:CHZ podbijecka.jpg|A picture of a Czech narrow gauge
Narrow gauge
A narrow gauge railway is a railway that has a track gauge narrower than the of standard gauge railways. Most existing narrow gauge railways have gauges of between and .- Overview :...
ballast tamper /track tamper .
File:Banbury's Amey Plc track tampers.png|A pictures of a Amey Plc
Amey plc
Amey plc, previously known as Amey Ltd and Amey Roadstone Construction, is a United Kingdom based infrastructure support service provider. It was once listed on the London Stock Exchange but since 2003 it has been a subsidiary of Spanish company Grupo Ferrovial, S.A....
track/ballast tamper in Banbury
Banbury
Banbury is a market town and civil parish on the River Cherwell in the Cherwell District of Oxfordshire. It is northwest of London, southeast of Birmingham, south of Coventry and north northwest of the county town of Oxford...
.
File:Banbury Amey plc train 1.png|A picture of Amey Plc
Amey plc
Amey plc, previously known as Amey Ltd and Amey Roadstone Construction, is a United Kingdom based infrastructure support service provider. It was once listed on the London Stock Exchange but since 2003 it has been a subsidiary of Spanish company Grupo Ferrovial, S.A....
ballast/track tamper train at Banbury
Banbury
Banbury is a market town and civil parish on the River Cherwell in the Cherwell District of Oxfordshire. It is northwest of London, southeast of Birmingham, south of Coventry and north northwest of the county town of Oxford...
station.
File:Banbury Amey plc train 2.png|A picture of Amey Plc
Amey plc
Amey plc, previously known as Amey Ltd and Amey Roadstone Construction, is a United Kingdom based infrastructure support service provider. It was once listed on the London Stock Exchange but since 2003 it has been a subsidiary of Spanish company Grupo Ferrovial, S.A....
ballast/track tamper train at Banbury
Banbury
Banbury is a market town and civil parish on the River Cherwell in the Cherwell District of Oxfordshire. It is northwest of London, southeast of Birmingham, south of Coventry and north northwest of the county town of Oxford...
station.
File:Duddeston Amey plc train.png|A picture of Amey Plc
Amey plc
Amey plc, previously known as Amey Ltd and Amey Roadstone Construction, is a United Kingdom based infrastructure support service provider. It was once listed on the London Stock Exchange but since 2003 it has been a subsidiary of Spanish company Grupo Ferrovial, S.A....
ballast/track tamper train at Duddeston
Duddeston
Duddeston is an inner-city area of the Nechells ward of Birmingham, England. It was part of the Birmingham Duddeston constituency until that ceased to exist in 1950.-Etymology:...
station.
File:Banbury Balfor Beaty train 4.png |A picture of Balfour Beatty
Balfour Beatty
Balfour Beatty plc is a British construction, engineering, military housing, rail and investment services company. It is one of the largest construction companies in the UK, and the 15th largest in the world...
ballast/track tamper train at Banbury
Banbury
Banbury is a market town and civil parish on the River Cherwell in the Cherwell District of Oxfordshire. It is northwest of London, southeast of Birmingham, south of Coventry and north northwest of the county town of Oxford...
station.
File:Banbury Balfor Beaty train 1.png |A picture of Balfour Beatty
Balfour Beatty
Balfour Beatty plc is a British construction, engineering, military housing, rail and investment services company. It is one of the largest construction companies in the UK, and the 15th largest in the world...
ballast/track tamper train at Banbury
Banbury
Banbury is a market town and civil parish on the River Cherwell in the Cherwell District of Oxfordshire. It is northwest of London, southeast of Birmingham, south of Coventry and north northwest of the county town of Oxford...
station.
File:Balfor_Beaty_track_tamper_at_Banbury_2005.JPG|A picture of a Balfour Beatty
Balfour Beatty
Balfour Beatty plc is a British construction, engineering, military housing, rail and investment services company. It is one of the largest construction companies in the UK, and the 15th largest in the world...
and Carillion ballast tamper/track tamper train at Banbury
Banbury
Banbury is a market town and civil parish on the River Cherwell in the Cherwell District of Oxfordshire. It is northwest of London, southeast of Birmingham, south of Coventry and north northwest of the county town of Oxford...
station in the year 2005.
File:Banbury Carrilion train 1.png |A picture of Carillion ballast/track tamper train at Banbury
Banbury
Banbury is a market town and civil parish on the River Cherwell in the Cherwell District of Oxfordshire. It is northwest of London, southeast of Birmingham, south of Coventry and north northwest of the county town of Oxford...
station .