MITCHELL, S.D. (MITCHELLNOW) A grain train derailment near White Lake in May was caused by a phenomenon called thermal misalignment,  also known as a sun kink, according to Ringneck and Western Railroad officials. The rail lines buckled because of sudden temperature swings that jumped from the 40s to over 80 degrees that week. No injuries were reported, and cleanup crews quickly restored the tracks. A similar heat-related derailment happened near Pierre around the same time. For more Government stories from MitchellNow.com, Click Here.