The body for the Millennium Locomotive consists of one of the most valuable and demanding rare metals: platinum. Platinum, the chemical symbol Pt, has a specific weight of 21.45 grams/cubic cm. It is almost twice as heavy as lead and clearly heavier than pure gold. Platinum is resistant, safe against corrosion and chemically resistant. It is a poor conductor of heat and expands very little; for these reasons the original meter and kilogram units are made of platinum. Platinum is so ductile that a 3,000 meter long wire can be drawn from just a gram of this metal. All of these characteristics make platinum a desired raw material in industry, chemistry, and medicine. A third of the world's production of this metal is used for jewelry. Because of its high degree of hardness, platinum requires only very small amounts of other metals; a standard content of 950 can be processed for jewelry. 950 parts out of 1,000 parts weight are platinum (compared to the usual 750 standard content for gold).

These extraordinary characteristics must be paid for dearly in the truest sense of the word, because platinum is very rare. The most important sources of platinum are in South Africa, Russia, Canada and South America. Miners must dig up to 2,000 meters deep for platinum ore. Even in the most productive mines platinum occurs only in trace amounts and is accompanied by other metals such as palladium, rhodium, ruthenium, iridium, and osmium, and also gold, nickel, copper and cobalt, depending on their presence. A total of 150 mechanical and chemical processes are required to extract pure platinum from the ore. These processes take a full five months.

For an ounce of 999 standard content platinum, ten tons of ore have to be mined and processed. The annual production of platinum is thus only about 160 metric tons, compared to 3,000 metric tons for gold.

These figures make it clear why platinum is so rare and valuable. There was jewelry and decorations made of platinum as far back as ancient Egypt around 700 BC and in Columbia. And the Spanish conquerors found it in 1590 in the rivers of Ecuador. In the search for gold they didn't know what to do with it and called it "Platina" and threw it back into the water. One reason that the advantages of platinum were realized so much later was its high melting point of 1,773 degrees Centigrade/3,223 degrees Fahrenheit. Heat of this magnitude to process platinum could not be reached until the discovery of the oxyhydrogen burner in the middle of the 19th century. Even today processing platinum requires traditional hand labor technology and special experience.