Involute Engg Industries Private Limited (IEI) has been a leader in the manufacture and indigenous development of electro-mechanical and electro-pneumatic equipment for railway transportation since its establishment in 1984. The company focuses on import substitution in this critical sector, significantly contributing to the local industry.

IEI has developed a range of essential spares and sub-assemblies for the N-32 Tap Changer, a key component in A/C Electric Locomotives. As a primary supplier of railway components, including camshafts and precision gearboxes, IEI serves major clients such as Bombardier and Adtranz. The company also caters to the maintenance needs for tap changer and circuit breaker spares across Electric Loco Sheds in India under various zonal railways.

In 1995, IEI took on the challenge from BHEL to develop and supply the complete SMSC (D.C. Controller) for WCAM2, WCAM3, and WCAG1 Electric Locomotives, previously imported from Switzerland. IEI successfully delivered 170 units, which are now in operation under the Western and Central Railways in Mumbai. Additionally, the company has innovated Eddy Current Clutches for 3100/3300 HP Diesel Electric Locomotives for DLW in Varanasi, showcasing its commitment to advancing railway technology in India.