LKAB mining company needed to upgrade four T46 terminal locomotives because they had reached their technical life length and lacked the tractive effort to handle the new longer and heavier trains. The first idea was to buy new locomotives, but none suited LKAB’s specific requirements. The next idea was to turn to a locomotive rebuilding company. Unfortunately, the company closed down, forcing LKAB to do the rebuilding. This paper describes how the mining company turned locomotives built in 1973 into modern environmentally friendly, state-of-the art locomotives, tailor-made for the specific requirements and conditions of LKAB in operating iron ore transports in Kiruna Sweden. LKAB was the first company in Europe to meet the European emission regulation 3A/EPA (US Tier 2) by installing a diesel engine in a loco and therefor the name of the loco was T46 Green Power Concept (GPC). The most important result was the discovery that a mining company, or any other company, can rebuild a locomotive to meet the company’s specific requirements and tailor it to its operation, if it is important to do so, provided skilled people are available for this task. The money spent was equal to the cost of purchasing new locomotives, and delivery time was equal to having the rebuilding subcontracted out.