Track Design for Line Speed Improvements - Research Paper Example

May 3, 2009 Track Design for Line Speed Improvements Introduction Turnouts are discontinuities in a track structure that are needed to move a rail vehicle from one track to another. These can cause derailment due to abrupt changes in the track which in turn produces excessive force levels. The design is to have a mixture of a conventional passenger traffic running at 150 kilometres per hour and a freight of 100 kilometres per hour. In diverging routes, continuities create a need for speed restrictions. In obtaining a higher diverging speed, it is necessary to completely replace an existing turnout with a new one. However, new designs are more costly. The main purpose of the study is to redesign a curve of transition between a curve and a straight track. This is to facilitate the construction of a turnout on a section that is straight. The construction of the curve is to allow access for freight traffic converge into a new intermodal freight depot and access of the main lines will be required at a minimum speed of 50 kilometres per hour and 50 trains will be expected to use the railroad track everyday. A track handbook must be discussed with the railway staff senior officer for a suitable turnout for the traffic usage and speed. Route Surveying for condition By definition, route surveying is composed of all survey operations needed for the design and construction of the engineering works such as railroads. The system of a route surveying is associated with design of a highway and its construction. This contains four separate and inter related processes. Reconnaissance and planning is the first in the inter related process. Reconnaissance in the method of gathering of the possible data found in the area. Planning is the method of preparation of all the work to be done. The design of the improvements of the projects are then worked out for the implementation. Transportation infrastructure and the other major projects requires the taking of real properties, or right-of-way. The would be cost of the partial takings, commercial properties, remainder damages, court costs, utility relocations and other related right-of-way items are very difficult to anticipate. Accuracy in the estimate procedures are used to facilitate the budgeting and timely completion of the projects. The construction work is the actual implementation of all the processes which takes from reconnaissance and planning. Components required for the route improvement The centreline of the railroad track is the reference point used in railroad surveys. This is stationed at 20 metres chord in curves, and stations have references at valuation points. The stationing is one of the components of the route improvement of the railroad track. The route is to have stations in order to determine the locations of obstructions along the route of work. The offset distance is the specified line or curve. This is implemented as a pair of 2lines or curves that are of equal distance from the point of original line or curve. Profile grade is a vertical alignment required for all roadway or computation of the track design. The vertical alignment data is provided for the description of the alignment in the design. Vertical curves are required at any intersection of different road/rail gradients. The design are done so that the rate of change of the vertical acceleration is gradual for the safety and comfort of the commuters and the incoming vehicle would be visible for a safe distance. The horizontal curves are used to change the alignment, and direction or the slope of a railroad. Curves that change the alignment are called the horizontal curves Offset stakes are used primarily to catch point and will produce a slope stake information. The location of the slope stake is dependent to the position of the pivot point where the slope begins. Slope stakes are used in highways and track works for the location of the toe of slope or the top of the cut. The economic and environmental arguments for the expanded railway network had the support from the government agencies in the recent months, addressing at the "Delivering a Sustainable Railway"(Verslype, 2008).The railway system that is sustainable can be achieved across the continent with the hope of improvement of the railway. As the people strive towards the development of the of an expanded network, the expectations must be in consideration with the formulation of a guided strategy. The improvement work of the track of the railway management encompasses the construction, transportation, mechanical processes and electrical matters. The track design on requirement on route must be taken into consideration, the materials, turnout, track structure and maintenance/management , track repair standard and railroad maintenance operations. The procedures of track laying and the inspection of the survey results are the same. Track approaches may need different track works. A traditional ballast tracks is concerned is concerned about the smoothness of the route while the non-ballasts tracks uses alignment design data for comparison and for fine adjustment of the route. The inspection involved in the final track pavement positioning are different. Identification of the Current effect of Rail Forces on Route The railroad tracks have permanent speed restriction. There are reasons for the restrictions. The poor condition of the track components and the formation is considered. Another poor condition is the drainage problem. There are many drainage problems along the route or the railroad. The accommodation of more passenger depends on the improvement of the railroad track. The drainage along track must be improved or removed. The improvement of the railroad will benefit the commuters and the train operator too. The minimum speed of the passenger train will be 50 kilometres per hour after the improvement. This will convince more commuters to use the train for their travel. The additional number of trains to travel on a daily quota to meet the population requirements would at least be 50 trains. With the freight services that would carry goods from one end of the track and back would mean more farm producers will be able to sell their fresh produce because of the fast delivery of the goods. Fresh produce from the farm to the market will consume a shorter time of travel. The end consumers will be enjoying the freshness of farm foods. Its improvement will encourage more commuters to use the train due to the fact that part of the redesigning of the railroad track is to increase the minimum speed of the train. The access line will be requiring the train to travel at the improved track at a minimum speed of 50 kilometres per hour. Consideration of formation, Drainage and Ballast The earthwork slope is not the only one being affected, and the incidence of high density rainfall will result in drainage problem of the track and the deterioration of the quality of the ballast. When the formation becomes soft, problem arises. A sudden change in the stiffness of the formation is also one cause of the problem. A very good example of which is the stiffness of the formation, that is located in the interface of the normal ballasted track and under bridges. An improvement of the drainage which is done locally in situations is the representation of a partial solution of the stiffening of the ballasts in order to cope with the loads, is considered where the regular maintenance would be required. The review done by the Department of Transportation, showed that the railway transport shows a haul air journey. It is clear that one challenge for the railway industry is the decrease the travel time. The railway Safety and Standards Board(RSSB) did published in 2003, stated that the following are the main effect of climate change in the railways. Extreme temperature affects the tracks and extreme precipitation affects the earthworks. Drainage system is also affected by the extreme precipitation while the overhead line equipment is affected by extreme wind. Accordingly, the most commonly affected is the effects on drainage and the earthworks infrastructure. Professor Alec Skempton published in his paper, the subject in the 1950's and in the 1960's the culmination in his paper (geotechnique, vol. 20, September 1970) the mechanism of the failure became clear. He observed that is was the high pore water suctions induced in the freshly constructed slopes that had induced in the freshly constructed slopes that ensured the short and medium term stability. The pore water desipate, and the process is being accelerated near the slope that is exposed to the rain into the body of slope. The infiltration of water into the cracks that are formed in the soil during the dry season will eventually hasten the instability of the slopes. The mechanism that persist in railway embankments are similar but unknown factors come into the picture. The origin of the geological materials in the embankment, the method in the installation, and the level of compaction used in the construction could be an example. The toe crest drainage system at the location of the earthwork with counterfort or herringbone slope drains clearly has a vital role in the stability of the slopes. Vegetation plays an important role because it assists the stability of the slope through a combination of reduced water content and the reinforcing of the roots. The burrowing of animals may undermine the suitability of the railway in some soils. In view of these factors, the railway system is undertaking the inspection of its earthwork assets. In 2004, the plan was that, the earthworks would be inspected in accordance with the railway standards. In the report of the 16,000.00 kilometres of the major earthwork, 6% of it were in poor condition and 25% were marginal. The railway with poor condition requires an annual inspection and that of the marginal assets requires an inspection of one inspection every 5 years. Curved Track Requirements Scope is one of the several curve requirements for the gauge in the construction of railroad track. alignment and surface of track and the elevation of the outer rails and the limitations of speed for the curved track. Measured between the heads of the rails at a 90' with the rails is the gauge on a plane, 5/8 of an inch below the top of the rail. Alignment may not deviate from the uniformity of the amount prescribed, and the end of the line must be at points on the gauge side of the line rail. The end of the chord must be on the side of the gauge of the outer rail. The elevation and speed limitations, the outside rail of the curve may not be lower than the inside rail, and the maximum allowable operating speed for the curve is computed by the following formula: where: Vmax = Maximum allowable operating speed (miles per hour) Ea = Actual elevation of the outside rail (inches) d = Degree of curvature (degrees) If the curve is elevated, the elevation must be provided throughout the curve unless physical conditions does not permit. If there is an elevation runoff that occurs in a curve, the actual minimum elevation must be used in the computation of the maximum allowable operating speed for the curve. The elevation runoff must be at a uniform rate, within the limits of track surface deviation, and it must extend at the full length of the spirals. The track surface applies to maintain the surface of its track within the limits prescribed. Interpolation of speed between track classes means in the event that the track geometry related defect is detected in a track geometry car inspection, the railway may, use interpolation to determine the speed of the temporary slow order initiated to the protection of the defect. Switch and Crossing Design The railroad switch, turnout or points is a mechanical installation enabling railway trains to be guided from one track to another at railway junctions. Diagram of a right-hand railroad switch, rail track A divides into two: track A divides into two: track B(straight Track) and track C(diverging Track) The switch has a pair of linked rails which is known as points(switch rails or point blades) that is lying between the diverging outer rails. These points are moved into one of two positions to determine if a train coming from a narrow end will be led to the straight path. If the switch is locked, a train coming from either of the converging railroad tracks will pass through the points towards the narrow end regardless of the position of the points. The vehicle's 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 the narrow end and a diverging track leaves to the opposite side. A straight track is not always present. There are times that both tracks may curve on opposite sides or maybe both tracks may curve with a differing radii, in the same direction Clearance The overhead clearance is the perpendicular distance between the top of the highest rail and the lowest point of the overhead structure and/obstruction. The side clearance is the shortest distance between the centrelines of a track and a structure, or the trackside obstructions such as downspouts, ladders, piles of materials, equipments or inventory and others. The track clearance is the shortest distance between the centrelines of the railroad tracks that are adjacent to each other. The overhead clearance above the top of the rail of standard railroad track, for the transportation of conventional railroad cars. It will be 22 feet, or otherwise provided, the minimum overhead clearance above the top of the rail on tracks inside buildings is 17 feet. The side clearance from the centerline of a curved railroad track is minimal, and will be 1 inch/30 minutes of curvature for the additional minimum side clearance from the centre line. 8 feet is the least side clearance for structures and obstructions above the top of the rail. Track Renewal Methodologies and their Varying Efficiencies Track renewal deals with maintenance optimization, that is linked with track monitoring. Optimized cost maintenance can be achieved as maintenance strategies being placed to suit the set of needs. There are means of establishing accurately the possible extent of maintenance needed in the tracks. The research will include the study of the options, procurement of materials maintenance with the use of the right materials and adopted QA program. The optimal control of damaging impacts, and detection of whell flats, as well as the study of optimal monitoring of rail wear and fatigue condition of track, with new innovative methods, systems and sensors. The study of optimal track maintenance, together with rail maintenance techniques, such as grinding, lubrication, recharging in curves and replacement of rail. To obtain the innovative track renewal methods, which is faster then the classical methods, especially for embedded tram tracks. The refurbishment methods for rails in curves and for special track work, extending their normal life with at least a factor to a review of the existing maintenance strategies. The track maintenance standards in order to reduce the maintenance costs by at least 20%, combined with an improved track quality and improved performance and the establishment of a harmonized European track maintenance standard. The extension of track maintenance is needed with its quantified effect on LCC, comfort and safety The maintenance strategies for the existing tracks, including that the contract procurement of components, and the control of damaging impacts, including the monitoring and maintenance techniques of preventive and predictive maintenance schemes. Possession Regime for Works The meaning of the word, possession regime for works is that the contractor who is working on a certain job order has the right to suspend the railway operations on lean hours in order to give way to the construction or improvement of the railroad track. If it is very necessary that the construction needs to be done immediately, there is a commitment of the management of the railway activities to suspend the operation of the railways in liew of the ongoing construction or improvement of the railway. Interfaces with other Engineering Functions (e.g. track/overhead) There are railway projects that are isolated, at the same time, there are communication cases that are required between control centres. Station based systems and line control system interfaces with each other. There are cases that heavy rails, with a new or upgraded railway system, that connects to the existing lines, are built for different needs and with the older technology. The efficient possession and isolation for the maintenance of the line, the inter-operability between the old and new is critical in ensuring that the trains runs smoothly and safely without the interruptions across the interfaces. However, it is very frequent that the found interface between the control rooms does not function correctly. A great cost and disruption is undertaken in the reworks. Railway control centre interfaces can have better designs for inter-operability, for the management of a safer and efficient and improvement of train running. Required Transition Design The design for transition of the track is the combination of horizontal and vertical curve. The horizontal curve is within the 50 kilometre stretch. The curves are connected to other curves and a straight track. The design analysis of the converging horizontal curves and the design load of the railroad track will depend upon the capacity of the railroad track to carry. If the railroad track is to carry 50 passenger trains a day and the freight will be twice as much, then the design capacity must also consider the minimum speed of the passenger train and the freight train. The design will include the present existence of several stations, a number of bridges and tunnels. The slope vertical gradient are covered under the vertical curves and the sharp curves are covered under the horizontal curves. The design of the railway will most likely have a traffic flow that must have a heavy axle weight in order to run with the increased weight of 20 to 25 tonnes daily. Selected Turnout Design for the New Freight Facility The turnout design for the new freight facility turned out to be a well designed project. The 50 kilometre track was redesigned in order for the railway to accommodate heavier load than before thus making the freight of goods faster and with a bigger volume. The design in the merging of the railroad tracks will prove that with proper planning and implementation of designs will make travelling safe and comfortable. Conclusion The design that was done and implemented in the design transition of two adjacent railroad tracks have better services that before. With the addition of 50 passenger trains, and freight trains 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 railroad track at a minimum speed of 100 kilometres per hour with a heavier weight will prove that better designs done are more advantageous. The commuters will have a shorter travel time with safer trains to ride on and with an offer to have a more comfortable travel. The freight train will be able to accommodate more goods for transport, with better handling and shorter time to reach the destination. . 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.html'slopestaking 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) 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 FHWA, 2003. "Acquisition for the 90's." URL: http://www.fhwa.dot.gov/realestate/acq90s.pdf (Accessed on 28 June, 2003). Marcel Verslype, Executive Director, European Railway Agency http://www.publicserviceevents.co.uk/ppt/ri08_marcel_verslype.pdf Skempton, Alec (geotechnique, Vol. 20, September 1970) http://www.fabermaunsell.com/media/5236.pdf Read More