The passenger was ordered to move and refused. The rule was grossly unfair, yet the carrier within its rights to enforce it. The traveler’s belligerence may have added fuel to the fire, though by no means could he have anticipated its horrifying outcome. There were racial overtones. And fellow travelers who witnessed it expressed outrage and shock. A description of United Airlines Flight 3411 on April 9, 2017? Yes — but also of the Savannah Special over the rails of North Carolina, 70 years earlier, almost to the day. On April 5, 1947, Atlantic Coast Lines train conductor C. A. James shot to death Fletcher H. Melvin for refusing to move from a whites-only car. Like the crew on United Airlines Flight 3411, James was merely enforcing his company’s rules, then mandated by Southern segregation laws. And like David Dao, the Vietnamese-American doctor dragged off the United flight, Melvin, a 24-year-old African-American hospital orderly, was obligated to comply. The United incident, caught on multiple passengers’ cell phones, involved a fully booked flight to Louisville on which the airline needed to seat four crew members traveling to staff another plane. No passengers took up the company’s offer of cash and a hotel room to relinquish their seats, so the airline exercised its right to select four at random, including Dao and his wife. He resisted, and airport security officers bloodily removed him, dragging him down the aisle. If the incidents are haunting in their similarities, they also illustrate the peculiar, and often contradictory, dual goals of transportation law enforcement. Crew members and security personnel are responsible for both assuring the safe passage of riders (think Pinkerton agents riding shotgun on stage coaches) and enforcing the company’s rules. In a conflict, company interests generally prevail. That’s not to say there shouldn’t be any rules. Disagreements between travelers and transport personnel are as old as the wheel or the idea of paying someone to take you someplace. The customer isn’t always right or inclined to behave safely and respectfully to everyone aboard. Laws against smoking, fare evasion and tampering with equipment only work if enforced, and the authority for doing so belongs to crew members ranging from locomotive engineers to flight attendants.That authority results in Draconian enforcement, however, when used capriciously to uphold debatable policies that aren't relevant to safety. In Virginia, lawmakers were so intent on institutionalizing Jim Crow that in 1919 the Legislature codified every bus driver and train crew member as “a special policeman (with) all the powers of conservators of the peace,” including pursuit and arrest. In case of any doubt, they added, “he shall be … the judge of the race of each passenger.” Other Southern states similarly deputized and indemnified bus and train crews. While historians recount threatened lawsuits on behalf of Melvin, scant details remain of any ramifications to the conductor who killed him. Segregation is thankfully a relic of the past; by no means does United’s overbooking policy equate with one of America’s most shameful chapters — though comments reportedly overheard from Dao have increased suspicions that he and his wife were profiled for removal. Security has also changed with the times, and intensified. The post-9/11 world can no longer afford to be cavalier about threats. Secretly armed air marshals evoke comfort more than fear. But the greatest safety practice is in preventing or lessening potential confrontation, which is where United dismally failed. If the airline truly needed the four seats for crew members, shouldn’t it have prevented the unlucky passengers from boarding in the first place? Though the scene might not have been pretty at the gate, it’s far easier to shut a jetway door than to physically remove a paying passenger from a seat. In a statement the day following the incident, United CEO Oscar Munoz called it “an upsetting event to all of us here at United” and apologized for having to “re-accommodate these customers,” sparking further condemnations of insensitivity. Two days later, Munoz pledged to no longer use law enforcement “to remove a booked, paid, seated passenger.” The Chicago Department of Aviation placed on leave the three aviation security officers involved in the incident, for actions “not in accordance with our standard operating procedure” and “obviously not condoned by the Department,” spokeswoman Karen Pride said in a statement. She said the officers were unarmed. In that, United Airlines Flight 3411 is a long way from the Savannah Special conductor. But what remains is a basic tension between the rights of company and passenger that hasn’t changed much at all. Robin Washington writes frequently about transportation and civil rights and was executive producer of the PBS documentary “You Don’t Have to Ride Jim Crow!” He can be reached at firstname.lastname@example.org or via Twitter @robinbirk.