** Shares of railroad operator CSX CSX.O fall ~1% to $27.04 in extended trading

** Company reports Q1 profit of 34 cents/shr, below analysts' estimates of 37 cents/shr, according to data compiled by LSEG

** CSX reports Q1 sales of $3.42 bln, below analysts' estimates of $3.47 bln

** Company's coal shipping volume decreased by 8.5% in Q1

** Company's operating margin for the quarter decreased to 30.4% from 36.3% in the same period last year

** As of last close, stock down 15.3% YTD

(Reporting by Kamal Choudhury in Bengaluru)

((Kamal.Choudhury@thomsonreuters.com;))