WASHINGTON — Twitter wars are common enough between people of opposing political views, some celebrities, or various social-media influencers.

But between Amtrak and one of its host railroads?

A Wall Street Journal report (behind a paywall) notes that Amtrak and Norfolk Southern have been trading letters about an Amtrak tweet last month in which the passenger railroad blamed delays on the northbound Crescent on “Norfolk Southern freight train interference.”

That led to a letter to Amtrak from an NS lawyer saying the tweet on the @AmtrakAlerts feed was advancing “a misleading narrative that operates at the expense of Norfolk Southern’s reputation” and that further tweets would mean NS “will be forced to consider further action.”

NS said the delay was actually because a sleeping and dining car decoupled after the train left New Orleans.

Amtrak responded with a letter noting that after the initial mechanical issue, the train sustained more than three hours of additional delays because of freight trains — and cited 11 instances in of delays it said it had suffered because of Norfolk Southern.

The Journal story notes the underlying and ongoing issue in Amtrak’s relationship with its freight railroad hosts: a lack of performance metrics to show how host railroads perform and the accompanying lack of enforcement of the law giving Amtrak trains preference over freight trains. The most recent ruling in the lengthy legal battle over those performance metrics would allow them to be developed by Amtrak and the Federal Railroad Administration. [See “Court ruling opens door for FRA, Amtrak to establish on-time performance metrics,” Trains News Wire, July 20, 2018.]

The letter to NS from William Herrmann, Amtrak vice president, senior managing deputy general counsel and assistant corporate secretary, suggested that Norfolk Southern’s “further action” should be “taking immediate action to improve the on-time performance of Amtrak trains on your railroad.”