As Wall Street begins to worry about economic growth, railroad stocks could be in for a rough ride, according to Citi. Analyst Christian Wetherbee downgraded three rail stocks — CSX , Norfolk Southern and Union Pacific — to neutral from buy, saying in a note to clients Thursday that a slowing economy would hurt investors in those companies. "Rails have outperformed, with relative valuation improving over the last six months, and earnings growth expectations are the highest. This combination will likely limit relative performance in a potentially decelerating demand environment," Wetherbee wrote. A sluggish future for rail stocks does not even require a full economic contraction, according to Citi. "We are not fully baking in a recession across any of our coverage, but rather an environment in which the US avoids a recession, but consumer spending pivots meaningfully toward services and goods are sluggish," Wetherbee wrote. Those three stocks are all down sharply for the year, but CSX and Union Pacific have held up better than the S & P 500. Here are the price target changes associated with the downgrades, and the upside from Wednesday's closing price. CSX Corp.: to $35 from $45, upside of 8.3% Norfolk Southern: to $260 from $345, upside of 9.4% Union Pacific: to $235 from $287, upside of 4.4% — CNBC's Michael Bloom contributed to this report.