Jim Cramer ranks the most investable stocks in the industrial space, which includes railroad operators, manufacturers and aerospace plays. : CNBC's Jim Cramer has been pinpointing the most investable stocks in sectors from health care to energy, and on Wednesday, he turned to what he called "the most fraught cohort in this entire market": the industrials. "If there's one thing I know from running a hedge fund, it's that the industrials become very tough to own when interest rates are rising," the "Mad Money" host said after the Federal Reserve reaffirmed its aggressive rate hike agenda.