In 1991 following the Tehran metro Company´s decision to speed up the construction of Tehran metro by switching the execution policy from in-house assignment to EPC contracts , Metrosaz company was founded to host the engineers and experts who during the years of working directly for Tehran Metro Co gained valuable experience and expertise .Especially in lines 1 and 2 of Tehran Metro which Metrosaz Co. had an important role to its implementation , these expertise was outstandingly manifested .By expanding the metro lines in Tehran , Metrosaz company expanded its subject of activity in to engineering consultancy in order to participate in different fields of metro construction .Therefore Metrosaz as a mother company had to establish other specialized companies to contribute as much as possible in different aspects of metro construction and operation.