TRACK QUALITY INDEX AS TRACK QUALITY ASSESSMENT INDICATOR

TRACK QUALITY INDEX AS TRACK QUALITY ASSESSMENT INDICATOR Dian Setiawan M Civil Engineering Department Faculty of Engineering Universitas Muhammadiyah Yogyakarta Jl. Lingkar Selatan, Tamantirto, Kasihan, Bantul, Yogyakarta, 55183 dian_setiawanm@yahoo.co.id Sri Atmaja P. Rosyidi Civil Engineering Department Faculty of Engneering Universitas Muhammadiyah Yogyakarta Jl. Lingkar Selatan, Tamantirto, Kasihan, Bantul, Yogyakarta, 55183 atmaja_sri@umy.ac.id Abstract Track Quality Index (TQI) is used in order to evaluate track quality. In this paper, TQI application for Indonesian Railway (IR) has been reviewed and various methods to evaluate track quality have been presented. IR have been used TQI-Geometry in infrastructure maintenance works and accident investigation. UK SD Index, Netherlands Q Index, USA TRI, FRA TGI, Austrian TGI, Canadian TQI, SNCF’s MDI, Chinese TQI, Polandia J Coefficient, Indian TGI, and European Standard are some methods to evaluate track quality. However, their results rely only on a limited number of parameters and aspects of track deterioration. Those methods cannot provide a thorough indication of all influencing parameters and their role in track degradation. The author suggests that main track degradation should have 4 aspects: Track Super-Structural; Track Sub-Structural; Track Geometrical; Traffic, and furthermore, a new TQI should be developed by combining 3 index investigations: Track Irregularity, Track Settlement, and Track Geometry. Keywords: Track Quality Index, Track Degradation, Track Structure, Track Geometry, Traffic Parameters Abstrak Track Quality Index (TQI) digunakan untuk mengevaluasi kualitas jalan rel. Penelitian ini membahas penggunaan TQI dalam perkeretaapian Indonesia dan menyajikan berbagai metode yang digunakan untuk mengevaluasi kualitas jalan rel. Perkeretaapian Indonesia menggunakan TQI-Geometrik pada pekerjaan pemeliharaan infrastruktur dan investigasi kecelakaan. UK SD Index, Netherlands Q Index, USA TRI, FRA TGI, Austrian TGI, Canadian TQI, SNCF’s MDI, Chinese TQI, Polandia J Coefficient, Indian TGI, dan European Standard merupakan beberapa metode lainnya yang dapat digunakan untuk mengevaluasi kualitas jalan rel. Namun, hasil dari metode-metode tersebut hanya terbatas pada beberapa parameter dan aspek kerusakan jalan rel dan juga tidak dapat menyajikan indikasi terperinci dari semua parameter yang berpengaruh dan perannya terhadap kerusakan jalan rel. Penulis menyarankan kerusakan jalan rel sebaiknya terdiri dari 4 aspek: struktur atas jalan rel, struktur bawah jalan rel, geometrik jalan rel, dan lalulintas, serta selanjutnya dikembangkan TQI terbaru yang merupakan kombinasi dari 3 investigasi index: Track Irregularity, Track Settlement, and Track Geometry. Keywords: Track Quality Index, Kerusakan Jalan Rel, Struktur Jalan Rel, Geometrik Jalan Rel, Parameter Lalulintas INTRODUCTION The construction of railway networks involves a large amount of financial support imposing, not only at the conception and design level, but also during the line operation, a demanding, a complete, and a rigorous estimation of the total cost involved in the life cycle of the system. Furthermore, due to the running of high-speed trains and heavy haul trains, the track equipment is damaged more frequently, leading to a threat of running safety. However, maintenance of railway tracks is both costly and difficult to manage effectively. 1 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 It is due to the fact that there are a large number of parameters influencing the rate of track degradation. Therefore, railway industries are trying to improve the productivity of their maintenance teams through more effective control of track deterioration (Sadeghi and Askarinejad, 2007). By using appropriate tools for estimating railway network life cycle costs (LCC), it is possible to minimize the final cost and, at the same time, to identify the most important aspects and parameters influencing the cost evaluation. Research is not only required on the LCC modeling, but also on the estimation of major degradation factors and the assessment of its impact on the maintenance needs (Berawi, et.al, 2010). How to evaluate the quality, and improve the maintenance of track equipment is scientifically becoming an urgent issue to ensure the railway operation safety, reliability, and rational allocation of resources. Track Quality Index (TQI) is figures of merit that objectively quantify the condition of track. TQI can monitor track degradation and maintenance operation, can summarize and display the condition of large sections of track, and are correlated with both safety standards and values of ride quality (Hamid and Gross, 1981). This paper review TQI application for Indonesian Railway and present various methods to evaluate the track quality from several recent literatures in order to understand more about aspects and parameters that affects railway track deterioration and to propose the main aspects and parameters to determine TQI analysis. EXISTING TQI-Geometry APPLICATION FOR INDONESIAN RAILWAY Railway Infrastructure Maintenance Peraturan Menteri Perhubungan No PM 32 2011 about standard and procedure of railway infrastructure maintenance, stated that the railway track maintenance is to fullfil railway operation standard and TQI Value which has been assigned. On that regulation, TQI for railway track is not mentioned and explained as detail as TQI for railway bridge and tunnel which have been determined based on the classification of deterioration level i.e. A, B, C, and S and completed with sheet of entry and rating index of degradation assessment. Railway Accident Investigation by The National Transportation Safety Committee Track Condition In this paper, author presents the example of TQI application on the train accident analysis reporting. According to The National Transportation Safety Committee (2010), in the location of train (KA) 80 derailment, wooden sleeper was obsolescent about 33,7% 43, 8%. The worst condition found where there were 5 obsolescent wooden sleeper successively. Rail fastening on those broken wooden sleeper also would not work properly in curvature. Rail fastening cannot withstand the centrifugal force appearing on train that travel in curvature, and it result in the outer rail crumple up. Therefore, this condition will endanger the train travel especially in curvature, sloping track, and bridge. Sumber: The National Transportation Safety Committee, 2010 Gambar 1 Track Condition 2 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 Track Recording Car Track recording car is used to measure the geometry of railway track line. The result of geometry measurement will depend on the track material condition. Bad material condition will reduce the life of track counted from the date of the last measurement, while the dynamic factor of track will affect the stability of a train travel. From the result of geometry measurement by track recording car, geometry tolerant value is given to decide the follow up of measurement, whether it needs to do track speed reduction, immediate maintenance, or railway track line rehabilitation. There are various tolerant value given in some countries, with consequence is that the smaller the tolerant value, the more maintenance cost. Currently, track recording car used by PT Kereta Api Indonesia (Persero) is EM120. Geometry measurement using track recording car will produce some parameters, such as gauge, raising, listring, and superelevation. Four parameters are then summed to obtain the value of TQI. TQI has no unit, because even the unit of the sum (mm) is same but it is different in vector. Indonesian TQI is classified into 4 sections and converted as track condition category I to IV. The classification of track condition category is intended as suggestion of improvement and determination of the maximum speed on the related track. Tabel 1 TQI Classification and Determination of Track Maintenance Work Parameter Category 1 Category 2 Category 3 Category 4 Gauge 0 – 5 mm 6 – 10 mm 11 – 15 mm > 15 mm Tamping 0 – 5 mm 6 – 10 mm 11 – 15 mm > 15 mm Listring 0 – 5 mm 6 – 10 mm 11 – 15 mm > 15 mm Superelevation 0 – 5 mm 6 – 10 mm 11 – 15 mm > 15 mm Total (TQI) 0 – 20 21 – 40 41 – 60 > 60 Speed (Km/Hour) 100 < Vmax < 120 80 < Vmax < 100 60 < Vmax < 80 Max < 60 Condition Comfort Safe Caution Danger Immediate Very Immediate Action Maintain Treat Repairment Repairment Tabel 2 Measurement Result of Track Recording Car EM-120 Segmen JR - KLT JR - KLT JR - KLT JR - KLT JR - KLT JR - KLT JR - KLT JR - KLT KM From To Device Type Length (m) Cat TQI TQI Total Super elevation Tamping Listring Gauge 209.800 210.000 210.180 210.189 210.200 210.400 210.600 210.800 210.000 210.180 210.189 210.200 210.400 210.600 210.800 211.000 LRS LRS BH LRS LRS LRS LRS LRS 200 181 9 11 200 200 200 200 3 2 2 2 2 2 2 2 43.3 35.8 37.4 39 35.7 22.5 28.5 26.6 16 14.5 18.8 8.7 13.8 8.7 9.9 9 17.1 10.1 12.6 19.4 16.1 11.4 12 12.1 7.8 9.2 2.7 8.9 3.4 0 4 3.2 2.4 2 3.3 2 2.4 2.4 2.7 2.3 On above table, it is concluded that track section where train derailment occur is determined as category 2 that stating the track classification as “SAFE (aman)” condition so that the suggestion of improvement is “treat”. The action of treat as improvement suggestion means that the action needed is to repair minor damage with the aim of improving the track condition. Lifting of listring at certain points must also be taken to improve railway track construction dimension. Nevertheless, the result of measurement by the track recording car, in fact, does not represent the whole condition of track, whereas this measurement is very important to determine the maintenance works that should be made and the maximum speed on the related track. 3 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 VARIOUS METHODOLOGIES FOR EVALUATING TRACK QUALITY For further evaluation, some methods from several literatures by which track quality index can be obtained are discussed below: UK SD Index SD index consists of seven standard deviations {σi = 1, 2,…., 7}, each of which is associated with a track quality parameter and is calculated from measurement values for the parameter over a track segment, as formulated in (1). The larger the SD index is, the worse the track segment is in some aspect represented with the quality parameter (Liu et al., 2015). ……………………………………..(1) where σi is the standard deviation of a quality parameter in mm, xij the measurement value in mm for the parameter at the jth sampling point in the track segment, and n the number of sampling points in the track segment. Track quality index of United Kingdom, Australia, and so forth are like the SD index. Differently, they apply (1) to different lengths of track segments. Netherlands Q Index ProRail of Netherlands converts the SD index into a more universal form across different classes of tracks, as shown in (2) (where N denotes the Q index for a quality parameter over a 200 m long track segment, σi is the standard deviation for the quality parameter, and σi80 represents the 80th percentile of standard deviations for 200 m long segments in a maintenance section ranging in length from 5 to 10 km). The Q index ranges from 10 to 0. The larger the Q index, the better the track quality of a 200 m long track segment (Liu et al., 2015). ………….…………….………(2) USA Track Roughness Index Track roughness index was proposed in 1998 by America Amtrak (Liu et al., 2015). It is the average of squared measurement values for a quality parameter over a track segment, as shown in below: ……………………...…..………………(3) FRA Track Geometry Index Track geometry index TGIi uses the measurement value space curve length Li for a quality parameter over a track segment to quantify the quality of the track segment, as shown in (4). A larger TGIi indicates that the track segment has a worse quality (Liu et al., 2015). 4 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 ………………………………….(4) where Li is the measurement value space curve length for a quality parameter over a track segment, L0 the length of the track segment, and yj the milepoint of the jth sampling point on the track segment. Austrian Railway Track Geometry Index Austrian Railway uses the five-parameter track defectiveness (w5) calculation for data obtained from geometry recording cars. The defectiveness for each parameter in each evaluated track section is the ratio of the length sum of subsections that have exceeded the acceptable deviation to the total length of the section. In other words, defectiveness for each measured track parameter is calculated from the following formula (Madejski and Grabozyk, 2000 in Sadeghi, 2010): ………………………………………..…….(5) where Li= length of subsections that have exceeded the acceptable deviation and L= total length of the track section. Assuming that the geometry parameters have negligible effects on each other, each geometry parameter is treated independently. Therefore, from the probability theory, the five-parameter defectiveness is defined as follows: ……………..…….(6) where wz and wy=arithmetic averages for the vertical and horizontal irregularities, respectively, as determined from the defectiveness of the left and right rails; wg=defectiveness of cross level; ww=defectiveness of twist; and we=defectiveness of the track gauge. The amounts of deviations are calculated over a chord length of 18.9 m. Austrian Railway uses this method to rate the track geometry condition using the tabulated values presented in Table 3 (Madejski and Grabozyk, 2000 in Sadeghi, 2010). Tabel 3 Track Condition Based on w5 Value Canadian Track Quality Index Canadian National Railway Company (CN) uses a 2nd order polynomial equation of the standard deviation σi of measurement values for a quality parameter over a track segment to assess its partial quality, as formulated in (7) (where C is a constant and takes on the value of 700 for the main line tracks). The overall quality assessment is achieved by averaging six partial quality indices for gauge, cross level, left (right) surface, and left (right) alignment (Liu et al., 2015). ..........................................................(7) 5 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 A larger track quality index implies the track segment has a better quality. SNCF’s Mean Deviation Indices SNCF’s indices are different from other indices. They are not based on standard deviations but on weighted moving average over a track segment, as illustrated in: ……………………..…….(8) where y0 is the maximum milepoint value in the track segment and ɳi(y) the measurement data for a quality parameter at the milepoint y (Liu et al., 2015). Chinese Track Quality Index Like SD index, both national railroads and Nanjing Metro in China mainland use the sum of standard deviations of seven quality parameters to assess the overall track quality of a track segment, as formulated in (9). There are two lengths for the overall track quality assessment, 200 m and 500 m. The track length of 500 m is applied to high-speed railroads. Of course, the track length of 200 m is at the same time adopted for track segment quality assessment. The larger the value of TQI, the worse the track segment in the overall track quality (Liu et al., 2015). ...................................................................(9) Polandia J Synthetic Coefficient J synthetic coefficient is used as an indicator of the track quality based on the standard deviation evolved by Polish Railways (Madejski & Grabczyk, 2002 in Berawi et al., 2010). Four track geometry parameters are considered in this index: vertical irregularities, horizontal irregularities, twist, and gauge. The equation for calculating J synthetic coefficient is: .....................................................(10) where Sz, Sy, Sw and Se are the standard deviation of vertical irregularities, horizontal irregularities, twist, and gauge, respectively. The standard deviation for each measured parameter is calculated by the following equation: .........................................................(11) Based on the above equation, n is identified as the number of signals registered on the track being analyzed, xi represents the value of geometry parameters at point i and x is the average value of the measured signals. The J synthetic track quality coefficient also specifies the allowable deviation of J, determining the track condition with respect to the state defined by the track operating appropriately on one side and the track requiring maintenance on the other. 6 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 Table 4 Allowable deviations of J coefficient based on line speed (Madejski & Grabczyk, 2002 in Berawi et al., 2010) Indian Railways Track Geometry Index (TGI) Indian Railways has developed a formula to represent the quality of track called TGI. This model is based on the standard deviation of different geometry parameters over a stretch of 200 m segment. TGI is calculated for each segment and the average value of such segments in every km gives the general TGI value (Talukdar et al., 2006 in Berawi et al., 2010). With respect to the effect of each geometry parameter on the ride quality, TGI has given different value for various geometry parameters as shown in the following formula: ..........................................................(12) where UI, TI, GI, and AI are the index for unevenness, twist, gauge, and alignment respectively. For each measured track parameters, the index is calculated from the relation: ..................................................(13) where SDmes is the standard deviation of measured geometry parameters, SDn represents the standard deviation prescribed for newly laid track and SDmaint is the prescribed standard deviation for maintenance. The standard deviation values used in Equation 13 are specified in Table 5. For the classification of track condition according to the required maintenance is shown in Table 6. Table 5 Standard deviation (SD) values (Sadeghi, 2010) Table 6 TGI Classification for maintenance (Talukdar et al., 2006 in Berawi et el., 2010) European Standard EN 13848-5 The rail track geometry can also evaluated in accordance with European Standard EN 13848-5 (CEN, 2005, in Berawi et al., 2010). Three track geometry parameters are 7 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 considered: longitudinal level, alignment, and gauge. The measurement of longitudinal level and alignment are conducted based on the standard deviation of irregularities on a 200 m long segment, while the irregularities on the gauge is measured based on a mean value of 100 m long segment. Apart from that, specification of geometry irregularities with wavelength domain in the range of 3 m < λ ≤ 25 m is another required parameters to be calculated in the standard deviation. The allowable thresholds for geometry parameters based on the European Standards are given in Tables 7-8. Table 7 SD Threshold values for profile and alignment (CEN, 2005, in Berawi et al., 2010) Table 8 Distance limit between specified gauge and mean over 100 m segment (CEN, 2005, in Berawi et al., 2010) ASPECTS AND PARAMETERS TO TRACK DEGRADATION According to Sadeghi and Askarinejad (2007), some recent studies have been intended to investigate the rate of track degradation which have led to the development of several track degradation models. They have mostly concentrated on one particular aspect of the railway track system. Their results rely only on a limited number of parameters and in each study they considered only one of many aspects of the track deterioration and in turn, took into account those parameters directly related to this aspect. This method cannot provide a thorough indication of all influencing parameters and their role in the track degradation. To provide a cost effective and efficient railway track maintenance, a thorough appreciation of all the parameters is needed even if they are seen from different aspects. In this research, author suggests that main track degradation should have 4 (four) aspects: Track Super-Structural Aspect; Track Sub-Structural Aspect; Track Geometrical Aspect; and Traffic Aspect, and furthermore, track quality index assessment is therefore conducted as combination of 3 (three) index investigation: Track’s Irregularity Index (Track Super-Structure aspect; Sleeper and Rail), Track Settlement Index (Track SubStructure aspect; Ballast and Track Sub-Layers), and Track Geometry Index (Track Geometrical aspect). Based on the various literatures review and analysis, the track deterioration parameters from the four aspects of track super-structure, sub-structure, geometry and traffic parameters are investigated. Track structural parameters include rail-pad stiffness and rail type, fastening condition-fastening type, sleeper condition-sleeper type, ballast conditions-ballast type, and subgrade compaction (Sadeghi and Askarinejad, 2012; Sadeghi and Askarinejad, 2007). Track geometrical parameters are gauge (trackplane), 8 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 profile (longitudinal vertical plane), alignment (horizontal plane), cross-level and twist (transverse vertical plane), sleeper spacing, listring-tamping works, drainage condition and initial track geometry index (Sadeghi and Askarinejad, 2012; Sadeghi and Akbari, 2006 in Sadeghi, 2010; Sadeghi and Askarinejad, 2007). Traffic parameters consist of tonnage, train speed, axle loads and load cycles (Sadeghi and Askarinejad, 2007). New track quality index should be developed and established by combining these 3 index investigation including the more complete track deterioration parameters from the four aspects of track super-structure, track sub-structure, track geometry and traffic parameters. CONCLUSION In this paper, TQI application for Indonesian Railway has been reviewed and various methods to evaluate the track quality have been presented. From the results obtained in this research, the following conclusions are given. TQI-Geometry was applicated not only in Indonesian Railway Infrastructure Maintenance works as stated in PM 32 2011, but also in Indonesian Railway Accident Investigation by The National Transportation Safety Committee. However, in PM 32 2011, TQI for railway track is not mentioned and explained as detail as TQI for railway bridge and tunnel which have been determined based on the classification of deterioration level i.e. A, B, C, and S and completed with sheet of entry and rating index of degradation assessment. On the other hands, The National Transportation Safety Committee used 4 parameters (gauge, raising, listring, and superelevation) to obtain the value of TQI and it classified TQI into 4 sections and converted as track condition category I to IV. The classification of track condition category is intended as suggestion of improvement and determination of the maximum speed on the related track. Nevertheless, the result of track condition classification, in fact, does not represent the whole condition of track. So it is clearly seen that there is a distinction between TQI application in Indonesian Railway maintenance regulation and in Indonesian Railway accident investigation. UK SD Index, Netherlands Q Index, USA Track Roughness Index, FRA Track Geometry Index, Austrian Railway Track Geometry Index, Canadian Track Quality Index, SNCF’s Mean Deviation Indices, Chinese Track Quality Index, Polandia J Synthetic Coefficient, Indian Railways Track Geometry Index, and European Standard EN 13848-5 are some methods to evaluate the track quality. Those methods have mostly concentrated on one particular aspect of the railway track system. Their results rely only on a limited number of parameters and in each study they considered only one of many aspects of the track deterioration. Those methods cannot provide a thorough indication of all influencing parameters and their role in the track degradation. A thorough appreciation of all the parameters is needed even if they are seen from different aspects to provide a cost effective and efficient railway track maintenance. The author suggests that there are 4 (four) main track degradation aspects: Track Super-Structural Aspect; Track Sub-Structural Aspect; Track Geometrical Aspect; and Traffic Aspect, and a new track quality index should be developed and established by combining 3 (three) index investigation: Track’s Irregularity Index, Track Settlement Index, and Track Geometry Index. Track structural parameters include rail-pad stiffness and rail type, fastening condition-fastening type, sleeper condition-sleeper type, ballast conditions-ballast type, and subgrade compaction. Track geometrical parameters are gauge 9 Simposium XIX FSTPT, Universitas Islam Indonesia, 11-13 Oktober 2016 (trackplane), profile (longitudinal vertical plane), alignment (horizontal plane), cross-level and twist (transverse vertical plane), sleeper spacing, listring-tamping works, drainage condition and initial track geometry index. Traffic parameters consist of tonnage, train speed, axle loads and load cycles. 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Jakarta, Indonesia. Talukdar, K., Arulmozhi, U., Prabhakar, K. & Satyanarayan, 2006. Project Presentation Improvement of TGI Value by Computer Analysis. Ministry of Railways Indian Railways Institute of Civil Engineering, India. 10 View publication stats