DF4 1842 had just rounded the last horseshoe curve below Pingkouxia with westbound train 245, the 22:45 Lanzhou to Wulumuqi passenger, on 15 January 1992. The train had already climbed 200m in the 18km since leaving Hexipu and still had another 300m and 22 km to go before it finally reached the summit beyond Jiling.