<p>In electric railway, creep phenomena occur in contact wires over extended periods due to the continuous application of tensile stress. To mitigate the effects of primary creep, a pre-stretch method is employed, wherein a tensile load greater than the service tension is temporarily applied to the wire. This process aims to reduce the primary creep strain in advance. However, the magnitude and duration of the overload used for this procedure vary across different countries, including Korea. In this study, various overload levels were experimentally applied to Cu-ETP contact wires during installation. The subsequent creep elongation under service tension was monitored over approximately one year. Based on the results, an optimized pre-stretching method was proposed to effectively minimize long-term creep in contact wires.</p>