[1][2] After 33 years of suspension, the project came into force in 1976 when groundbreaking took place in the presence of Prime Minister Süleyman Demirel on the western entrance at the Ayaş side of the mountains.
The next year in 1977, Deputy Prime Minister Necmettin Erbakan initiated the digging work at the tunnel's opposite entrance in the east near Erkeksu village.
[1] Bidding consortiums from France, Germany, Italy, United Kingdom and Belgium submitted tenders proposing the project's realization by financing through foreign loans instead of the unattractive build-operate-transfer method.
[2] The Minister of Transport, Maritime and Communication Binali Yıldırım stopped the high-speed rail project of Istanbul-Ankara and hence the Ayaş Tunnel construction.
[3] The opening of the line was seen as important for the development of tourism in the region, and would enable the transportation of one-million tons of trona mineral annually from Çayırhan mine.
It appeared that the cross section of the tunnel was insufficient to withstand the aerodynamic pressure of the high-speed rail even though the other railway infrastructure would have been improved.
[3] The ministry announced in February 2013 that studies were being conducted for the resumption of boring work for the remaining 2 km (1.2 mi) section of the tunnel.