Causes and treatment methods of turnout guardrail defects

1 Common turnout guardrail defects on conventional railways 1.1 The clamp does not measure the width of the groove at the end of the guardrail buffer section, causing abnormal wear of the guardrail. The daily guardrail clamp operation does not measure the groove width, resulting in insufficient groove width at the guardrail opening end, and the wheel back hits the end of the guardrail buffer section. It violates Article 3.9.4 of the "Revised Regulations" that the width of the wheel flange groove at the end of the buffer section shall not be less than 65mm, causing abnormal impact at the end of the guardrail buffer section. 

1.2 Only meausrement the width of the groove at the end of the buffer section of the guardrail is measured without measuring the value of 1370, resulting in abnormal wear of the guardrail exceeding the limit.

The Notice No. 121 of the Engineering Department of the Group Corporation requires that the distance from the working edge of the guardrail at the end of the buffer section to the working edge on the other side should be less than 1370mm, in other words, the track gauge should not be greater than 1435mm. From the on-site inspection, some foremen do not know the 1370mm value of the guardrail interval and the wing rail interval, do not measure them during daily inspections, do not know the causes of the defects, and do not handle the defects when they exist. The wear at the end of some guardrail buffer sections has not been handled for a long time, and the risks and hidden dangers of driving exist for a long time. The guardrail interval exceeds the limit here, and both the gauge and the support must be measured, and the diversion section must be determined through comprehensive analysis. 1.3 The straight section of the guardrail is not straight, causing the train to swing horizontally and wear the guardrail. The guardrail clip is not standard, the straight section is not straight and has a direction, the wheel flange groove width progressive size and progressive rate errors within the buffer section are too large, and the guardrail direction is poor. When the train passes the turnout, it has an uneven impact contact with the guardrail, which aggravates the wear of the guardrail. 

​​1.4 Poor frog angle The track gauges at the frog toe and heel are inconsistent. The angle measured by the chord line is poor. The frog deviates from the line direction at both ends. When the train passes through the frog, it produces a serpentine motion, which increases the impact force on the guardrail and causes abnormal wear of the guardrail.

1.5 Poor offset of guide curve

When the train is running on the guide curve, due to the centrifugal force, the train wheels run close to the upper rail of the guide curve. The small radius of the turnout guide curve, large wheelbase of the locomotive, large tonnage of the locomotive, high traffic density, high lateral passing speed and other factors cause side wear of the upper rail of the guide curve, track gauge expansion, and small offset. Poor offset is equivalent to the unevenness of the guide curve, which will aggravate the lateral swing of the train, especially the poor offset of the rear part of the guide curve, which will cause abnormal wear of the guardrail. voyeur awning 󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮

1.6 Horizontal overrun at the rear of the guide bend

The horizontal overrun at the guide bend is equivalent to the reverse compound unevenness, which is equivalent to the reverse super-height of the curve. Such a disease is the superposition of two unfavorable factors, the track direction and the reverse horizontality of the curve, at the same position, which increases the lateral swing of the train when passing the guide curve, causing abnormal wear of the guardrail. 

1.7 Guardrail installation error, abnormal impact on guardrail, wrong guardrail will cause the buffer section and straight section to be inconsistent with the design, and the impact force on the guardrail will increase when the train passes through the frog, causing abnormal wear of the guardrail. In particular, the CZ2009 series crossover and combined frog guardrails are related to the line spacing. The guardrail drawing numbers for different line spacings are different. Some guardrails have the same length but slightly different hole spacing. If you are not careful on site, they will go wrong. Once installed incorrectly, it will not only cause abnormal wear of the guardrail, but also pose a risk to driving safety. 

1.8 The train sways before the switch enters the guardrail. The poor condition of the line and switch before the train enters the guardrail causes the train to sway. Due to inertia, the train will also swing when it runs to the guardrail, especially the swaying within 8m before entering the guardrail in the switch, which increases the abnormal wear of the guardrail. voyeur awning 󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟

1.9 The main rail of the intersection turnout is not bent

The main rail corresponding to the 50kg9#CZ2214 crossing turnout guardrail should be bent. The specific dimensions are shown in the figure. If it is not bent, the lateral swing of the train when passing through the switch will be aggravated, increasing the impact force on the guardrail and causing abnormal wear of the guardrail.

1.10 The incorrect position of the switch is caused by the seamless welding of the switch rails, the insertion of extended rails in the switch with large rail gaps in winter, and the failure to confirm the position of the fork during the overhaul of the switch. For example, the width of the switch for the 50kg6#SC384 symmetrical switch is 33mm, and the corresponding guardrail enters the buffer section. The front and rear positions of the switch are incorrect, which will cause lateral swing when the train passes, increasing the impact force on the guardrail and causing abnormal wear of the guardrail.

1.11 The direction of the main rail is poor, causing the train to sway laterally and wear the guardrail. The direction of the main rail is poor. When the train passes through the switch, the serpentine movement will aggravate the impact force of the wheels on the guardrail, causing the guardrail to wear faster. voyeur awning 󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟

1.12 There is a curve before and after the turnout

Poor curve posisivity, poor superelevation along the slope, structural triangle pits formed by superelevation of the curve and the turnout guide curve, etc. will cause the train to sway. The train will start to sway before entering the turnout, and will also sway when entering the turnout due to inertia. The swaying of the train when entering the frog will cause guardrail wear.

2 Fault analysis

2.1 Control the groove width of each part of the guardrail. The groove width setting standard and ensure the correct shape and position of the guardrail can reduce the swaying of the train when passing through the switch, reduce the abnormal impact on the guardrail, ensure smooth driving and reduce the abnormal wear of the guardrail. awning awning

󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮2.2 Note that the cause of guardrail wear caused by vehicle swaying before entering the guardrail may not be in the guardrail, but caused by the vehicle swaying before entering the guardrail, especially the vehicle swaying within 8m before entering the guardrail in the turnout, which increases the abnormal wear of the guardrail. Therefore, when investigating abnormal guardrail wear, do not limit the search to the guardrail and switch, and comprehensively investigate and repair the turnout and connecting lines before entering the guardrail. awning awning

󠄾󠅑󠅝󠅕󠄪󠄡󠄣󠄢󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮2.3 Pay attention to whether the frog rail parts are installed correctly. If the guard rail is installed incorrectly, the buffer section and the straight section will not be consistent with the design. When the train passes through the frog, it will increase the pressure on the guard rail. The impact force on the guardrail will cause abnormal wear of the guardrail. If it is installed incorrectly, it will not only cause abnormal wear of the guardrail, but also pose a risk to driving safety. The main rail corresponding to the 50kg9#CZ2214 crossing guardrail should be bent. If it is not bent, it will intensify the lateral swing of the train when passing through the switch, increase the impact force on the guardrail, and cause abnormal wear of the guardrail. Incorrect front and rear position and angle of the switch can also cause abnormal wear of the guardrail.

2.4 Pay attention to the renovation of turnouts and front and rear connecting lines, especially pay attention to the renovation of multiple waves and complex diseases, and eliminate the vibration source of car shaking. voyeur awning 󠄢󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮

3 Remediation measures and suggestions

3.1 Remediation method "one measurement, two determination, three adjustment, four tightening, five re-inspection". First, measure: measure the minimum track gauge at the fork center, inspection interval, guardrail distance and guardrail groove width; second, determine: determine the standard width of the straight section of the guardrail, that is, the difference between the on-site track gauge and the standard track gauge is the increase or decrease in the standard wheel flange groove width; third, adjust: adjust the guardrail clips according to the standard to ensure the groove width is appropriate, first adjust the straight section, and make the groove width of the straight section of the guardrail as equal as possible, and then adjust the buffer section according to the incremental amount to control the groove width and gradient rate of the buffer section. The effective edge of the guardrail in the buffer section is a straight line; control the groove width at the end of the buffer section and the outer end of the opening section shall not be less than the standard value; fourth, tighten: tighten from the middle to both ends to release stress; fifth, re-inspect: re-inspect the inspection interval, guardrail distance, guardrail interval, wing rail interval, and re-tighten the bolts. awning awning 󠄡󠄣󠄢󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟�

3.2 Guardrail interval shall not be greater than 1370mm The guardrail interval shall not be greater than 1370m. In other words, the track gauge should not be greater than 1435mm (except for widening). If the track gauge is large, the support gauge must also be measured to reasonably determine the diversion section. awning awning

3.3 Correct the problem of poor frog angle or incorrect frog position. Adjust the frog by changing the track gauge or moving the frog back and forth to ensure that the frog is in the correct position. Adjust the uneven straight and lateral track gauge of the frog part. Use a chord to measure the frog angle and make track gauge adjustments. The difference in track gauge between the front and rear toes of the frog should not be greater than 1mm when the allowable speed is greater than 120km/h, and should not be greater than 2mm when the allowable speed is 120km/h or below.

3.4 Correction of the distance of the guide bend The distance of the turnout guide bend should be controlled within the range of +4mm and -2mm of the standard value. The absolute value of alternating positive and negative values ​​shall not be greater than 2mm. If the verse method is used to measure the roundness of the turnout guide curve, when measuring with a 5m chord, the continuous verse error should be controlled to be no more than 2mm, and the maximum and minimum difference should be no more than 3mm. 󠄮󠄾󠅑󠅝󠅕󠄪󠄡󠄣󠄢󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮

3.5 Bend the main rail of the intersection turnout according to the turnout drawing. The main rail corresponding to the 50kg9#CZ2214 intersection turnout guard rail should be bent according to the drawing. awning awning

3.6 Assemble guardrails according to the switch drawing Before replacing guardrails or when assembling switchouts during overhaul, select guardrails according to the switch drawing and ensure that they are installed correctly. awning awning 󠄡󠄣󠄢󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟�

3.7 Strengthen the maintenance of curves before and after the turnout, adjust the curve superelevation and superelevation slope, correct the direction of the curve, especially pay attention to easing the changes in the curve positron, try to shorten the wavelength of the train vibration cycle, and make the train enter the turnout smoothly. The curve after the switch should be well sloped with superelevation. If a structural triangular pit is formed between the curve after the switch and the switch, the superelevation of the curve after the switch can be appropriately reduced. The connecting curve (supplementary curve) should always be kept smooth and in a good direction. The curve positron points should be set at intervals of 5m, and the positron continuous difference should be measured with a 10m chord. The operation acceptance management value should not be greater than 2mm. awning awning awning awning 󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮

3.8 Strengthen the renovation of the turnout, especially within 8m before the guardrail. Strengthen the correction of the track gauge and the track gauge change rate at the turnout switch and within 8m before the guardrail, adjust the roundness of the guide curve, correct the track gauge at the guardrail, eliminate the main rail direction, the size of the turnout frame should be controlled within ±1mm of the standard value in the close-fitting section, and the other parts should be controlled within ±2mm of the standard value, eliminate the gap of the turnout top iron greater than 2mm, fully correct the turnout direction, strengthen the renovation of compound track unevenness, and reduce the vibration source of car shaking as much as possible. awning awning awning charnel charcoal 󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮

3.9 Replace the guard rail if it is seriously damaged. Make preparations before the guard rail is slightly damaged, and replace it in time if it is seriously damaged. voyeur awning 󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟�

3.10 Adjust the gap between the guardrail iron plate slot and the main rail. By loosening the guardrail iron plate tie bolts, replacing the deflected nylon casing, replacing the 13#15# large gauge block on the outside, etc., the gap between the guardrail iron plate slot and the main rail can be eliminated and the number and thickness of guardrail clips can be reduced. awning awning 󠅝󠅕󠄪󠄡󠄣󠄢󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟�

3.11 Turnouts and front and rear connecting lines are overhauled as the same unit to ensure that multiple groups of turnouts and front and rear connecting line straight lines in the turnout area are in the same straight line, eliminate bad direction of the turnout group and eliminate train swaying in the turnout group. awning awning 󠄪󠄡󠄣󠄢󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮

4 Requirements for guardrail maintenance

4.1 Guardrails must be replaced immediately when they reach damage standards

4.2 Guardrail gaskets must be of unified model and standard Guardrails must use anti-escape gaskets. The number of layers shall not exceed 3 and the total thickness shall not exceed 15mm. voyeur awning 󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟�

4.3 The width of each part of the guardrail wheel flange groove shall comply with the standard. The width of the straight section shall be kept the same within the allowable range. The buffer section shall be kept straight. The wheel flange groove width at the end of the buffer section and the outer end of the opening section shall be set according to the standard. When the lateral track gauge is widened, the lateral wheel flange groove width shall be widened by the same amount. awning awning 󠅢󠄟󠄮󠄾󠅑󠅝󠅕󠄪󠄡󠄣󠄢󠄧󠄩󠄡󠄩󠄧󠄩󠄧󠄩󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟�

4.4 The gap between the iron plate slot of the guardrail and the bottom of the main rail should be adjusted in time to reduce the number of guardrail clips.

4.5 The guardrail bolts should be equipped with anti-loosening nuts

 

If you'd like to know more knowledage, please contact me:

 

Alina Shen

Jinzhou Tiegong Railway Maintenance Machinery Co.,Ltd.

E-mail: jztg0115@163.com / alina@tiegong.net

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