Track Design for Line Speed Improvement - Essay Example

May 11, 2009 Track Design for Line Speed Improvement Introduction The economic growth, urbanisation and the increased mobility are boosting demand worldwide for the efficient transportation of people and goods. In order to meet these demands, transport links are experiencing resurgence. This is particularly true with the rail infrastructure for passenger and freight applications. Today's transportation is an area where the cost pressures, globalization and competition are driving the merging public and private interests, Rail agencies worldwide are facing common challenges that range from ageing infrastructure to increasing demand. In the US, many cities are investing in light rail to ease congestion, address climate change, and improve transportation efficiencies. In Europe, the same scenario is starting to unfold with a focus on light and heavy rail driven by the need for efficient transport links says Martin Baggot. The renaissance in rail is a part of a wider strategy by the governments around the globe to develop sustainable transport solutions that will reduce our reliance on fossil fuels, the decrease of the impact of freight on roads and transform local communities into globally connected hubs, Martin Baggot adds. A study had been done to improve the line speed of a section in a railroad track which has a length of 50 kilometres. The route is a twin railroad track that is joined track with a traffic that is a mixture of a conventional passenger traffic that is running at 150 kilometres per hour and a freight that runs at 100 kilometres per hour. The design would have to consider several sections of horizontal curves with sharp radii and steep vertical curves or gradients. It will also cover several stations and tunnels, including a number of bridges that are present. The line has power supply for traction through an overhead line electrification system. The new traffic flow will require traffic with a heavier axle weight to run (increasing from 20 to 25 tonnes). The design proposes a non stop tilting trains to run as well as the passenger stopping train. The study is very important because there is a current number of permanent speed restrictions that are imposed due to the poor condition of the track components and formation/drainage problems. The necessity to redesign a transition curve between a curve and a straight railway is to facilitate the construction of a single turnout on a straight section. This is to be installed to allow access for the freight traffic into the new intermodal freight depot. An access off the main lines will be required at a very minimal speed of 50 kilometres per hour and an additional of 50 trains are expected to use the track. Route Surveying on Condition There are different description of the different types of surveys used to provide condition data to assist in the prioritizing of the resurfacing and reconstruction schemes are the following. Deflectograph is used to measure the deflection of the road surface under standard load. The deflection that is measured is used for the assessment of the strength of the construction of the road. The sideway force coefficient routine investigation machine is used for the measurement of the wet skid resistance of the surface of the road. The course visual inspection survey is a coarse driven visual inspection of the condition of the road or footway surface. The detailed visual inspection survey is a detailed, walked visual inspection of the condition of the road or footway surface. The scanner is the surface condition assessment of the national network of roads. The scanner automatic machine survey measures the condition of the surface of the road under normal traffic condition or speed. The term route surveying is a composition of all the survey operations that are needed to be used in the design and construction of any engineering work such as buildings, highways and railroads. Route surveying is an associated system with the design of a highway and construction for that matter. The system contains a four inter related processes that are separated. The reconnaissance and planning is one of the inter-related process. This is a method of gathering the possible data found in the area in question and planning is the method of preparation of all the work to undergo in the actual construction. The improvements to be done in the design are then worked on for the implementation. In the infrastructure of transportation and other major projects will require taking of real properties, or the right of way. It takes a lot of undertakings before the would be costs of any partial takings, commercial properties, court costs, remainder damages, utility relocations and other related right of way items to be anticipated. There must be accuracy in the estimating procedures in order to facilitate the budgeting and the time of completion of the project. The actual implementation of the earlier mentioned processes is the construction work. Components required for the route improvement Railway surveys use the centreline of the railroad for its reference points. Reference points are stations which are at 20 metres chord in curve and at the valuation points. This is one of the components of the route improvement of the railroad track. The route is assigned with stations in order to determine the location of the results of the route surveying that was performed. These could either be some sort of obstructions or a good feature of the route that may do some good points to the project. The specified line or curve is the offset distance. This is an implementation of a pair of 2 lines or curves that are have equal distance from the point of the original line or curve. The profile grade is the vertical alignment required to all roadway or a computation of the track design. The description of the alignment in the design is provided by the vertical alignment data. At intersections of different road/rail gradients, vertical curves are required. The design had to be considered because of the rate of change of the vertical acceleration is gradual due to the safety and comfort of the commuters and the visibility of the incoming vehicle for a safe distance. Curves that change the alignment are termed as the horizontal curves. These are used to change the alignment and direction or the slope of the railroad. The offset stakes are used to catch points and produce a slope stake information. Its location is dependent to the position of the pivot point where the slope will begin. These slope stakes are being used in highways and railroad tracks in locating the toe of the slope or the top of the cut. The argument between the economic and environmental aspect for the railway network is supported by government agencies, thus addressing the "Delivering a Sustainable Railway"(Verslpe, 2008). The improvement of a railway system can be sustainable and achieved. The expectations must be in consideration with a guided strategy as the people strive for the development of the expanded network. The railway management incompasses the improvement of the track construction, transportation mechanical processes and electrical matters. The requirement on the design of the route is taken into account, with the materials, turnout, track structure and maintenance or management. Track repair standard and railroad maintenance operations. The methods of the laying and inspection of the survey results are the same. A different track work is needed in the approaches. a traditional ballast track is concerned regarding the smoothness of the route while the non ballasts tracks uses alignment design data for comparing and fine adjustment of the route. The inspection in the final track involves positioning is different. Identification of the Current effect of Rail Forces on Route Permanent speed restrictions are imposed on railroad tracks. The poor condition of the track component, the formation and the drainage problems along the route are among the several problems encountered. This could be dangerous to a speeding train because it could derail the track that will cause accidents to happen. Its improvement is in the forecast that the train will accommodate more people. he drainage along the tracks must have to be improved or removed. The improvement of the railways will benefit the train commuters as well as the train operators. The minimum speed of passenger train would be 50 kilometres per hour and the freight would be 100 kilometres per hour. The rate of speed of the passenger train will convince more commuters to use the train for their travel, instead of driving their own vehicles in going and coming from their work places or just any where for that matter. An additional of 50 convenient trains will be added to meet the design of the train travelling the railroad tracks on a daily quota. The freight services which carry fresh produce from one end of the track to the other end would mean that more farm producers will be able to sell their fresh products because of the fast delivery of the goods. The end consumers will enjoy the freshness of the farm foods. The improvement of the railroad tracks will encourage more commuters to use the train because a part of the redesigning scheme is the increase of the minimum speed of the train. The access line will require the trains to run at a minimum speed of 50 kilometres per hour. Consideration of formation, Drainage and Ballast The incidence of high density rainfall will result in drainage problem of the track and the deterioration of the ballast quality. The slope of the earthwork is also affected. Problem arises the moment the formation becomes soft. The sudden stiffness of the formation is also a cause of the problem. The stiffness of the formation that is located in the interface of the normal ballasted track under bridges is a good example of the stiffness problem. A partial solution of the stiffening of the ballasts is the improvement of the drainage, done locally. This is done to cope up with the loads. Regular maintenance is required for the stiffening of the ballasts. The review done by the Department of Transportation also reveals that the challenge for the railway industry is the reduction of the travel time. The railway safety and standards Board (RSSB) published in 2003, said that the main effect of climate change in the railways are the following. Temperature change affects the tracks and extreme precipitation affects earthworks. The overhead line equipments are affected by the extreme wind and the drainage system is affected by the precipitation. The earthworks and the drainage infrastructure are the most commonly affected. Professor Alec Skempton had published in his paper, the subject in the 1950's and in the 60's the culmination (geotechnique, vol. 20, September 1970) the mechanism of the failure are now clear. He had observed that the high pore water suctions induced in the freshly constructed slopes that induced in the freshly constructed slopes that ensured the stability with the short and medium terms. The infiltration of water into the cracks that are formed in the soil on the dry season hasten the stability of the slopes. Unknown factors of mechanism that persist in railway embankment are similar. The method of installation of the geological materials in the embankment and the level of compaction used in the construction are examples of unknown factors. The toe crest drainage system at the area of the earthwork with herringbone slope drains clearly has a vital role in the slopes stability. The vegetation is very important because it assists the slope stability through a combination of the reduced water content and the reinforcement of the roots. Animals burrowing may sometimes undermine the sustainability of the railway in soil. The earthwork that gives support tot he railway system would affect the action of man, animals, weather and the global warming effect. In consideration of these factors, the railway system is undergoing inspection of its earthwork assets. The plan was, the earthworks will be inspected in accordance with the railway standards in 2004. According to the report, 16,000.00 kilometres of the major earthwork, 6% of it are bad condition and 25% were marginal. The railway with bad condition would require an annual inspection and that of the marginal will require an inspection every after 5 years. Curved Track Requirements Several curve requirements in the construction of railroad tracks are the following. Scope is a requirement for the gauge, alignment and surface of track including the elevation of the outer rails and the speed limitations. The gauge is then measured between the heads of the rails at 90 with the rails in the plane 5/8 inch below the top of the rail. The alignment may not deviate from the uniformity of more than the amount that is prescribed and the end of the line must be at a point in the gauge side of the line trail. The end of the chord are to be points on the side of the gauge of the outer rail. In the elevation and speed limitation, the outside rail of the curve may not be lower than the inside rail, and the maximum allowable operating speed for the curve is determined by the formula. where: Vmax = Maximum allowable operating speed (miles per hour) Ea = Actual elevation of the outside rail (inches) d = Degree of curvature (degrees) Elevation of curved track run-off is defined as "if the curve is elevated, the elevation is provided throughout the curve unless physical conditions does not permit. If the elevation run-off occurs in a curve, the minimum elevation is to be used in its computation of the maximum allowable operating speed for the curve. The elevation run-off must be at a uniform rate that is within the limits of the railroad track surface deviation, and it must be extended at a full length of the spirals. Its track surface applies to maintain the surface of its track within the limits that is prescribed. The interpolation of speed between the track classes means that in the event that the track geometry defect is detected in a track geometry inspection of cars, the railway can use interpolation for the determination of the speed of the temporary slow order that is initiated for the protection of the defect. Switch and Crossing Design A railroad switch, point or turnout are mechanical installations that will enable the railway trains to be guided from one track to another at railway junctions. The figure will show how the trains will transfer from one track to the other. The design will be on a 50 kilometres span of a railroad track. The transfer from one track to the other and vice versa is indicated by the arrowheads on both ends. The red broken lines indicate the design of the track converging from one another. The design of the first converging track is on straight railroad track and the second converging track falls on a curved track. If we try to analyze further, the design of the second track converging with the other track is a combination of a reverse horizontal curve. The switch is a pair of linked rails known as the points(switch rails or point blades) that are lying between the diverging outer rails. These points can be moved from one of the two positions to determine if a train coming from the other end will be led to the straight path or vise versa. If the switch is locked, a train coming from either of the converging will be passing through the point towards the narrow end, regardless of the position of the points, and the vehicles wheels will force the points to move. A switch has a straight through track and a diverging route. Right hand switches have a diverging path to the right of a straight track and when coming from a narrow end and a diverging track leaves, going to the opposite side. A straight track may not be present all the time. There are times that both tracks could curve on the opposite sides or both tracks may curve with a different radius, in the same path. Clearance The perpendicular clearance between the top of the highest rail and the lowest point of an overhead structure and /obstruction is the overhead clearance. The clearance on the side is the shortest distance from the centreline of the track and a structure or any other obstruction such as the downspout , ladders piles of materials equipments and others. The shortest distance between the track clearance and the centrelines of the adjacent railroad tracks is the shortest distance. The overhead clearance above the top of the rail of a standard railroad track are used for the transporting of conventional railroad cars. It is 22 feet or approximately 8.5 metres or otherwise provided. The minimum overhead clearance above the top of the rail on tracks inside buildings is 17 feet or approximately 8.8 metres. The minimum clearance from a centreline of a curved railroad track is 1"/30 minutes of a curvature to be added to the minimum side clearance from the centre line. The side clearance should be at least 8 feet for structures and obstructions above the top of the rail. Track Renewal Methodologies and their Varying Efficiencies Maintenance optimization deals with the track renewal that is linked with the track monitoring. Cost optimized maintenance area achieved by the maintenance strategies that are placed to suit the set of needs. There are means of technically establishing accurately the possible extent of the track maintenance. The research maintenance will include in the study, options, procurement of materials with the use of the right materials and adopted QA program. The study of optimal monitoring of rail wear and fatigue condition of track, including the new innovative methods, systems and sensors. Optimal track maintenance which includes rail maintenance techniques, such as grinding, lubrication, recharging in curves and the replacement of rail. The objective is to obtain the innovative track renewal methods which are faster than the classical methods, more so for the embedded tracks. The fixing method for rails in curves and for special track works, that is extending the normal life with the least factor to a review of existing strategies for the maintenance. The standard maintenance of the tracks is to reduce the costs by at least 20% with the combination of the improved track quality and the improved performance and the establishment of a harmonized standard of track maintenance. The maintenance is extended with the qualified effect on the LCC, comfort and safety. The strategy for the maintenance of the existing tracks, with the inclusion of procurement of components and the control of impacts that would damage the monitoring and maintenance technique of the preventive and predictive schemes. Possession Regime for Works From the word itself, possession regime for work or jobs is, the contractor who has work on certain job order has the right for the suspension of the railway operations on lean hours in order give way to the work or improvements or clean up of the drainage system of the railroad track. If the work to be performed is very necessary, and if the construction needs to be done immediately, there is a commitment of the railway management to suspend whatever activities of the railway to give way to the to the ongoing construction or improvement in the railroad track. Interfaces with other Engineering Functions (e.g. track/overhead) In some railway projects, there are cases where the contractor experience isolation. This could be due to the fact that the construction of the railroad track is in a remote place. In cases of isolation, communication systems are required between control centres. Station based systems and line control systems interfaces with one another. Cases of heavy rails, with upgraded railway system that connects to existing lines, are constructed with other forms of technology. The possession and isolation that is efficient for the maintenance of the line , the inter-operational activity between the old and the new will be critical in ensuring that the train will run smoothly and safely without interruptions across the interfaces. However, it is very frequent that the interface between the control rooms does not function correctly. Cost and disruption is encurred in the networks. The designs of railway control centre interfaces can have better designs for the inter-operations, for the management of an efficient, safer and improvement of trains to be on the run. Required Transition Design The combination of horizontal and vertical curve makes the design of the transition of a track. The horizontal curve runs within the 50 kilometre stretch. The curves are composed of a reversed curves having two different radius, and then to a straight track. The analysis of the design of the converging horizontal curves and the design of the railroad track depends on the capacity of the railroad track to carry. The conditions in the design of the railroad track is to carry 50 passenger trains a day and the freight train is assumed to carry twice as much load as the passenger train. If will follow that the minimum speed of the trains is considered. The design will consider the present existence of several stations, a number of railroad bridges and tunnel.The slope vertical gradient are covered under the vertical curves and the sharp curves are under the horizontal curves. The railway design will have a traffic flow that will have a heavy axle weight in order to run with the increase load of 20 to 25 tonnes daily Selected Turnout Design for the New Freight Facility The design for the turnout of the new freight facility was well designed well. The 50 kilometre track which was redesigned for the railway to accommodate heavier load will make the freight of goods faster and with a bigger volume. Proper planning and implementation of the merging of the adjacent railroad tracks will prove that travelling will be safer and more comfortable. Conclusion The implementation of the design transition of the two adjacent railroads will have better services than before. The addition of 50 passenger trains, and the freight carriers with the condition that the passenger train will travel at a minimum speed of 150 kilometres per hour and the freight train travelling in the track with a minimum speed of 100 kilometres per hour carrying a heavier load will prove that tracks designed for maximum strength have more advantage. The commuters will be having shorter travel time with safer trains to ride on and to have a more comfortable travel. ON the other hand, the freight train will be able to transport more goods with better handling and shorter time to reach the destinations. References http://www.extranet.vdot.state.va.us/loades/IgrdsManuals/concept/APP_D./pdf http://www.tpub.com/inteng/11.htm http://update.carlsonsw.com/docu/survce/survCE_Help.htmlslopestaking http://en.wikipedia.org/wiki/railroad_switch Davis, Foote, and Kelly, 2004, Surveying, Kogakusha Company,LTD. Tokyo FHWA, 2003. "Acquisition for the 90's." URL: http://www.fhwa.dot.gov/realestate/acq90s.pdf (accessed on May 2, 2009) Baggott, Martin, Towards Efficient Transportation Networks, On The Right Track, May, 2007, GHD Newsletter, May 12, 2009. http://www.ghd.com.au/Rail_Enewsletter/article 1.htm. Skempton, Alec (geotechnique, Vol. 20, September 1970) http://www.fabermaunsell.com/media/5236.pdf Specific Authority 351.35(1) FS. Law Implemented 341.302(7), (8), 351.35(1), (2) FS. History-New 1-27-81, Formerly 14-57.03, Amended 7-27-97, 10-16-01 Surveying and Mapping, Surveying. 1999. PHD.com Publications. May 3,2009 http://www.pdhcenter.com/courses/l108/108content.pdf Verslype, Marcel, Executive Director, European Railway Agency http://www.publicserviceevents.co.uk/ppt/ri08_marcel_verslype.pdf Read More