On CNBC's “Mad Money Lightning Round,” Jim Cramer recommended buying Canadian National Railway Company CNI, saying it's “way too cheap.”CN and CSX CSX announced on Sept. 9 an agreement to develop a new intermodal service into Nashville, Tennessee.When asked about MP Materials Corp. MP, he said, “I think you're fine, but don't — please, don't — buy any more. You're fine with what you have.”Lending support to his choice, DA Davidson analyst Matt Summerville, on Sept. 2, maintained MP Materials with a Buy and ...