PT Kereta Cepat Indonesia China (KCIC) stated that the longest tunnel project for the Jakarta-Bandung High Speed ​​Train Tunnel 2 in Jatiluhur, Purwakarta, West Java, was completed. This means, 13 tunnels have now been connected.

1040 meter Tunnel 2 is longest. It is also very complicated because clay geology. When clay soil is exposed to water and air, it can lose bearing capacity of the soil by up to 80 per cent. For this difficult tunnel, special team came from China.

https://karosatuklik.com/terowongan-terpanjang-kereta-cepat-jakarta-bandung-rampung/