Turkish newspaper Sözcü writes a news.  There is collapse in YHT (Yüksek Hızlı Tren - high speed train) tunnel between Bilecik and Bozüyük. Width of 80 metre and height of 40 meter for crater.

A villager says he irrigated his field and left. After only 3 meters collapse happen. He was lucky. Police emptied houses around collapse zone.

photographs in Turkish newspaper = https://www.sozcu.com.tr/2020/gundem/yht-tunel-calismasinda-gocuk-5756061/

This tunnel is not yet used. It was under construction. Plan was 6,2 kilometre tunnel between Bilecik-Bozüyük. It is for Ankara - İstanbul YHT (Yüksek Hızlı Tren). It is famous 'Tünel 26' refer to train line 26.

Tünel 26 has many problems. In 2009 there was first collapse. Only after 1 kilometre of tunnel boring. When it happened Tunnel Boring Machine buried. Construction stopped. Contractor Cengiz İnşaat wanted to take out TBM but they stopped for many years because of legal problems according to I hear. 33 Milion euro TBM lied there many years.

See photographs in Turkish newspaper from 2009 collapse = http://www.yarin11.com/bilecik/bu-tunelin-altinda-servet-yatiyor-h3335.html

Turkish newspapers say new collapse happen after continuation of tunnel construction. But Cengiz İnşaat internet site have not YHT tunnel construction under 'Ongoing Projects'. I don't know maybe another company continue = https://www.cengiz-insaat.com.tr/devam-eden-projeler/

I think they took out tunnel boring machine. Railroad internet site demiryolu.net 28 February 2020 news say with pictures province governor visited construction site. Project director Cihan Erdönmez say TBM is extracted. They continue with classic NATM method. They are not using TBM = https://www.demiryol.net/bilecik-valisi-senturk-yht-tunelinde-incelemelerde-bulundu/

Because this tunnel is not constructed, YHT train take a detour at very low speed 70 kilometre/hour.