Staff members climb down a cliff to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

A staff member climbs down a cliff as he prepares to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

Staff members climb down a cliff to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

Staff members climb down a cliff as they prepare to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

Staff members climb down a cliff to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

Staff members climb down a cliff to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

A staff member climbs down a cliff as he prepares to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

Staff members climb down a cliff to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

Staff members climb down a cliff to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)

A staff member checks on the safety rope before climbing down a cliff to eliminate potential falling rocks above a tunnel of Houma-Yueshan Railway in central China's Henan Province, Aug. 9, 2018. Railway maintenance workers work on the cliff to clear loose rocks above a rail tunnel here during flood season. (Xinhua/Li Jianan)