GT26 locomotives have played an important role in the rail transport industry for many years. These locomotives have been welcomed by users and repairmen of the rail fleet for a variety of reasons, such as the simplicity of the systems design, the control system, the supply of spare parts and the ease of use of navigation equipment. On the other hand, due to outdated design and lack of modern operating and protection systems, some components of these locomotives need to be revised and upgraded. Therefore, the reconstruction of ten GT26 locomotives has been transferred to the MAPNA Locomotive Engineering and Construction Company (MLC) by the Railways of the Islamic Republic of Iran.