the hunger crisis in south sudan. we met this mother who walked for more than a month to get food for her eight month old, so weak he can barely eat, debora patta reports tonight in depth on the risk of starvation for millions. tonight s other top headlines, new video tonight of w.n.b.a. star brittney griner after 130 days in russian detention. and a terrifying moment in colombia, the deadly collapse killing at least four, including a one-year old. and we ll end tonight with the heartwarming story of a seven- year-old cancer patient s dream come true. this is the cbs evening news, with norah o donnell. reporting from the nation s capitol. o donnell: good evening, to our viewers in the west, and thank you for joining us on this busy monday night. we begin tonight with breaking news, and horrific scenes from america s heartland. an amtrak train knocked on its side in a missouri cornfield. at least three people were killed and there are reports of numerous injuri