Thermic welding is the process of seamlessly welding streetcar and railroad tracks. It is also known as the Goldschmidt Reduction process.

It was introduced by Johann ("Hans") Wilhelm Goldschmidt

Hans Goldschmidt

Johannes Wilhelm "Hans" Goldschmidt was a German chemist.Born in Berlin, he was a student of Robert Bunsen. His father, Theodor Goldschmidt, was the founder of the chemical company Chemische Fabrik Th...

 in 1895 when he patented the process in Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 under the corporate name of Goldschmidt AG. Goldschmidt AG is now part of the Degussa group of chemical companies http://www.degussa-history.com/geschichte/en/predecessors/goldschmidt.html.

In this process, thermite

Thermite

Thermite is a pyrotechnic composition of a metal powder and a metal oxide that produces an exothermic oxidation-reduction reaction known as a thermite reaction. If aluminium is the reducing agent it is called an aluminothermic reaction...

, a mixture of aluminum powder and iron oxides react to produce intense heat and molten iron that is used to fuse together the rails.