La Voz de Galicia reports ADIF has plans to investigate whether the water leak problem at As Maceiras tunnel is due to construction defects. ADIF (Administrador de Infraestructuras Ferroviarias) is the state-owned railway infrastructure manager in Spain.

The 8.266 As Maceiras tunnel is the longest high speed train (AVE) tunnel in Galicia region of Spain. Continuous leaks of water has been a headache for the train traffic for the relatively new tunnel.

Tunnel was built by a joint venture of FCC and Acciona onky 6 years ago.

La Voz de Galicia article says the initial analysis did not detect a direct relationship between the water inflows and the geology. This basically means that there are filling defects between the segments and the ground that means that the waterproofing does not work. The through investigation will find out if this is indeed the case.

https://www.lavozdegalicia.es/noticia/galicia/2021/11/11/adif-analizara-tunel-largo-ave-defectos-constructivos/0003_202111G11P4991.htm