Founded in 1953 by Dr. Josef Theurer and Franz Plasser, Plasser & Theurer is an Austrian family-owned industrial powerhouse headquartered in Vienna, with its primary manufacturing, research, and assembly plant situated in Linz, Austria. Widely acknowledged as the inventor of mechanized track maintenance, the company holds thousands of international patents and has manufactured and supplied over 17,000 heavy railway machines to national rail operators, transit agencies, and track contractors worldwide.

Plasser & Theurer designs and manufactures a comprehensive fleet of heavy on-track machines: continuous-action leveling, lifting, and tamping machines (Unimat, Dynamic Tamping Express), ballast distributing and profiling machines, dynamic track stabilizers (DGS), track renewal and laying trains (SUM, SUZ), ballast bed cleaning machines (RM series), mobile rail welding robots, and overhead catenary maintenance vehicles. Through its modern $E^3$ drive technology, the company leads railway decarbonization by delivering electro-hybrid, battery, and overhead line-powered yellow fleet vehicles.

Its machines maintain critical high-speed rail lines, freight networks, and metro systems globally, including the Shinkansen in Japan, TGV/LGV lines in France, the DB network in Germany, High Speed 2 (HS2) in the UK, Amtrak and Class I freight corridors in North America, the Dedicated Freight Corridors (DFC) in India, and China’s high-speed rail network.