客货共线铁路新型扣件研发与应用OA

[Objective]Mixed passenger and freight railways carry both passengers and freight,and their track structures must simultaneously meet the requirements of both passenger and freight transportation.Field investigations show that conventional fastenings on mixed passenger and freight railways suffer from defects such as rail suspension,shoulder gaps,fracture of bolts and elastic clips,and corrosion of metal components.These deficiencies fail to meet the requirements of freight railways for track strength and passenger railways for ride comfort and also pose certain safety hazards.Therefore,it is necessary to develop a targeted new fastening system.[Methods]Based on the performance requirements and interface conditions of existing mixed passenger and freight railways,the new fastening system adopted an elastically separated in-line structure with bidirectional limiting shoulders.First,static and dynamic finite element models were established for theoretical analysis.Then,fastening performance tests,including assembly fatigue,assembly static stiffness,and insulation resistance,were carried out,and pull-out resistance tests of post-anchored steel sleeves were also conducted.Finally,a ballastless track section inside a tunnel on a mixed passenger and freight railway was selected for installation and testing of the new fastening system.[Results]The theoretical results showed that the strength of the main fastening components and the support-block shoulders,as well as rail vertical and lateral displacements and various dynamic parameters,all met the requirements.All factory test results achieved the expected performance with reasonable safety margins.The pull-out resistance of the anchored sleeve reached 60 kN after 0.5 hours,meeting the train load requirement on the day of construction,and reached 100 kN after 2 hours,meeting the long-term train load requirement.In the test section,TQI decreased from 13.05 to 11.10,and the rail lateral displacement decreased from 1.2 mm to 0.5 mm.[Conclusion]The test results show that both the track geometric condition and dynamic performance are significantly improved in the section installed with the new fastening system,indicating good prospects for application and promotion.