Athens Mass Transit System
|Subsidiaries||OSY S.A., STASY S.A.|
In January 2011 the Greek government proposed a reorganization of the system, which involves reduction of the separate companies to just two, one for tram and rapid transit and one for conventional and trolley buses. In March 2011, the Greek Government passed Law 3920 to allow Athens Metro Operations Company (AMEL) to absorb Athens-Piraeus Electric Railways and Athens Tram and create a new company "STASY S.A." (Greek: ΣΤΑΣΥ Α.Ε.) Also ETHEL S.A. and ILPAP S.A. were merged in "OSY S.A." (Greek: ΟΣΥ Α.Ε.). The mergers were officially announced on June 10, 2011.  While mergers at the top management level took place quickly, integration of the former companies at operations and support level proceeds slowly.
As of July 2011, the Athens Mass Transit System consists of:
- OSY S.A. (Greek: ΟΣΥ Α.Ε.)
- STASY S.A. (Greek: ΣΤΑΣΥ Α.Ε.)
- The Athens Tram system, formerly operated by Tram S.A. which was a subsidiary of Attiko Metro S.A.
- The Piraeus-Kifissia urban railway (ISAP), formerly owned and operated by Athens-Piraeus Electric Railways. It is occasionally advertised as Athens Metro Line 1.
- The Athens Metro system, consisting of Metro Line 2 and Metro Line 3, formerly owned by Attiko Metro S.A. and operated by subsidiary AMEL (Attiko Metro Etaireia Leitourgias, Attiko Metro Operations Company)
- A suburban rail system using Hellenic Railways Organisation (OSE) lines, operated by TrainOSE S.A. under the name Proastiakos. The section between Piraeus, Magoula and Koropi is regarded as the urban part.
- A part of the OSE main line (between Piraeus and Aghios Stefanos) operated by TrainOSE S.A.
OSY and STASY (which absorbed the former companies ISAP, ILPAP, ETHEL, Tram, AMEL) as well as TrainOSE (for its Proastiakos department) are coordinated by Athens Urban Transport Organisation (Organismos Astikon Syngoinonion Athinon - OASA, Greek: Οργανισμός Αστικών Συγκοινωνιών Αθηνών - Ο.Α.Σ.Α.), a public company. ISAP, ETHEL and ILPAP were wholly owned by OASA S.A.
TrainOSE S.A., which absorbed the former Proastiakos S.A. in 2007, became independent of the OSE group in 2008 and is now a separate public company.
- «Πράσινο» στο νομοσχέδιο για τις αστικές συγκοινωνίες Naftemporiki Newspaper, 2011-01-12.
- Law 3920, Government Gazette issue A-33, 2011-03-03.
- Ministerial Decision 28737/2637, Government Gazette issue B-1454, 2011-06-17
- Ministerial Decision 28738/2638, Government Gazette issue B-1454, 2011-06-17
- "Archived copy". Archived from the original on 2006-02-07. Retrieved 2006-02-16.
- "Archived copy". Archived from the original on 2005-11-04. Retrieved 2006-02-16.
- "Archived copy". Archived from the original on 2009-03-01. Retrieved 2009-12-31.