Steel fibre reinforced concrete (SFRC) offers a promising alternative to conventional steel reinforcement when constructing railway tunnel linings due to its remarkable strength and excellent fire resistance. Nevertheless, a crucial inquiry persists: could steel fibres potentially facilitate the conduction and transmission of stray currents, resulting in corrosion similar to that observed in conventional steel reinforcement? To address this concern, instrumental methods in electrochemistry, including potentiodynamic polarization techniques, have been used to assess SFRC’s corrosion resistance. Experimental results highlight the inherent resistance of concrete reinforced with discrete and discontinuous steel fibres to corrosion induced by railway stray currents. However, it is worth noting that the presence of even a small quantity of NaCl, specifically 0.3 mol/L in the concrete pore solution, can significantly diminish its corrosion resistance.