Modal analysis of railway current collectors using Autodesk Inventor Andrzej Wilk, Slawomir Judek, Krzysztof Karwowski, Mirosław Mizan and Paweł Kaczmarek MATEC Web of Conferences, 180 (2018) 04004 Published online: 27 July 2018 DOI: 10.1051/matecconf/201818004004