RasonConTrans’ Rail Traffic Service held an autumn inspection with the purpose of safe railroading at the Tumangan-Rajin section and maintenance of-way and structures and found out issues of water discharge in Unra tunnel and at 306 km railroad section. It required arrangement all-out repairing works on building culvert boxes and pipes to improve the trouble.
The main difficulty was that there were granitic rocks in the place where the culvert pipe should be set and that the specialty vehicles could not reach the site. So it had to carry all the works in manual way. Nevertheless, with the help of Korean staff by crushing the rocks by hand the 100-meter culvert pipe was set in the depth of 6 meter above the Unra tunnel crown. The culvert boxes were reverted with the stone and concrete, additional water catching culverts had been installed and spoil banks had been filled.