en Railway track and structures Railway track and structures پژوهشي Research <div style="text-align: justify;"><span style="font-size:11pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">One of the main challenges in ballasted railway tracks is the vibration induced in the track superstructure and the surrounding environment due to train passage. These vibrations cause significant damage to both the superstructure components and nearby structures. To address this problem, injecting polyurethane into the ballasted superstructure has emerged as a potential solution.</span></span></span></span></span></span></span><br> <span style="font-size:11pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">Polyurethane refers to a class of polymers containing urethane bonds, which are formed through an addition reaction between an isocyanate group and an active hydrogen compound, such as a hydroxyl group. Because isocyanate groups are highly reactive, their reactions can progress without requiring elevated temperatures. As a result, polyurethane can be produced in various forms, including foams, films, elastomers, powders, liquids, and emulsions.</span></span></span></span></span></span></span><br> <span style="font-size:11pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="line-height:normal"><span style="font-family:Calibri,sans-serif"><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">This study investigates the effects of injecting an economical and readily available polyurethane into ballasted tracks to reduce environmental vibrations caused by rail vehicle passage, using numerical methods. First, a ballasted railway track was modeled based on the finite element method and validated against existing technical literature. Subsequently, three models were developed: a standard ballasted railway track (without polyurethane), a track with 50% polyurethane injection, and a track with 100% polyurethane injection. The effects of train-induced vibrations were analyzed in terms of the time histories of displacement and vertical acceleration at points surrounding the track.</span></span></span></span></span></span></span><br> <span style="font-size:10.0pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">The results indicate that with 50% polyurethane injection, displacement and vertical acceleration are reduced by 61.87% and 98.6%, respectively, compared to the standard ballasted superstructure. For 100% polyurethane injection, the reductions are 62.15% and 76.93%, respectively.</span></span></span></div> Railway Ballasted Superstructure, Polyurethane Injection, Environmental Vibrations Caused By Train Passage, Finite Element Method 1 16 http://ijrare.iust.ac.ir/browse.php?a_code=A-10-357-2&slc_lang=en&sid=1 Sina Ghahremani s.ghahremani96@gmail.com 180031947532846003029 180031947532846003029 No School of Railway Engineering, Iran University of Science and Technology, Tehran, Iran Seyed Ali Mosayebi mosayebi@iust.ac.ir 180031947532846003030 180031947532846003030 Yes School of Railway Engineering, Iran University of Science and Technology, Tehran, Iran Fateme Samimi s75.mona@gmail.com 180031947532846003031 180031947532846003031 No School of Railway Engineering, Iran University of Science and Technology, Tehran, Iran Jabbar-Ali Zakeri zakeri@iust.ac.ir 180031947532846003032 180031947532846003032 No School of Railway Engineering, Iran University of Science and Technology, Tehran, Iran