Shares of Norfolk Southern (NSC - Get Report) are back to flat on the day, after an early-morning decline hit the stock. Likely causing that decline was a downgrade to underperform by the analysts at RBC Capital. 

"Perhaps the love affair with the rails could be running out of steam," TheStreet's Jim Cramer, manager of the Action Alerts PLUS portfolio, said on CNBC's "Stop Trading" segment. 

While Cramer hasn't been a railroad bear, he has been hesitant about jumping on to some of the rallies. For instance, Norfolk's 34% rally over the past year is more reasonable than compared to the 80% gain CSX Corp. (CSX - Get Report) has seen. 

The consolidation among major rail companies is over, he added. 

Although Norfolk is a great company with a great CEO, its efficiency savings simply won't be enough. Add in the lack of coal demand and a big part of the company's shipping volume can no longer act as a positive catalyst. 

Coal demand isn't rebounding the way many people had hoped, as unnaturally low natural gas prices remain the preferred choice, Cramer said. Perhaps the sector has rallied too far, too fast, he concluded. 

At the time of publication, Cramer's Action Alerts PLUS had no position in companies mentioned.