The contractor of the project, OLYMPIC METRO Consortium (OMC), signed a contract on 19 June 1991 with the Greek State, represented by the Ministry of the Environment, Regional Planning and Public Works. This consortium consists of twenty three Greek, French and German firms. The scope of work of OLYMPIC METRO is "the design, construction and commissioning of the extension of the Athens Metro network." The contract was assigned by the Greek State to ATTIKO METRO A.E. on 7 February 1992. The members of the consortium are listed below:

Engineering Works SOGELERG INGENERIE, France
DE-CONSULT, Frankfurt, Germany
ADK, Athens, Greece
HAMBURG CONSULT, Hamburg, Germany
SOCIETE GENERALE DE TECHNIQUE ET D'ETUDES, France BERLINER VERKEHRS CONSULTING, Berlin, Germany
LAHMEYER INTERNATIONAL, Frankfurt, Germany

Civil Works and Track Works SOGEA, France
HOCHTIEF AG, Essen, Germany SPIE-BATIGNOLLES, France METON S.A., Athens, Greece AEGEK S.A., Athens,
Greece DOMIKA ERGA, Athens, Greece DUMEZ INTERNATIONAL, France CEGELEC, France

Electromechanical Works SIEMENS AKTIENGESELLSHAFT BERLIN-MUENCHEN, Erlangen, Germany
GEC-ALSTHOM, Paris, France CEGELEC, France
AEG SHIENENFAHRZEUGE GMBH, Berlin, Germany SPIE-BATIGNOLLES, France SIEMENS AE, Athens, Greece CGA-HBS, France
JS TELECOM, Louveciennes, France CSEE TRANSPORT, Montrouge, France

Overall Coordination Group Leader Co-Leader

SIEMENS AKTIENGESELLSHAFT INTERINFRA SA
Transportation Systems Group 16, rue de la
BERLIN-MUENCHEN Baume
Werner-von-Siemens-Str. F- 75008 Paris
P.O. Box 3240
W-8520 Erlangen

Consortium Representative Weiner Steinbrenner
Consortium Deputy
Representative Parviz Madjedi