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Red flags have long been used as warnings of immediate, imminent and potential danger. The warning is signaled by the combination of color and movement. These days, to red-flag something is to draw attention to a dangerous situation.

  • In auto racing, a red flag means the race has been stopped because of a dangerous situation.
  • On the beach, one red flag means dangerous surf conditions and two red flags mean the danger level is so high that the beach is closed.
  • The National Weather Service issues a Red Flag Warning when temperatures are high, humidity is low, and winds are strong, three conditions that combine to produce an increased risk of fires.
  • Red Flag Exercises are advanced aerial training drills held by the United States Air Force to simulate life-and-death air combat.
  • The Red Flags Rule requires many businesses and organizations to implement a written Identity Theft Prevention Program designed to detect the warning signs – red flags – of identity theft in their day-to-day operations.
  • Waving a red flag at a bull is a way of deliberately provoking it (most people know it is the motion that the bull reacts to, not the color).
  • In the 1600s, a slang term for the human tongue was a red rag. To wave a red flag at someone meant you were chatting with them. As Francis Grose said in the 1785 Classical Dictionary of the Vulgar Tongue, “Shut your potato trap and give your red rag a holiday.”
In 1804, the first steam locomotive was invented

It pulled 70 people a distance of ten miles. By 1850, the United States had more miles of railroad track than any country in the world. Mental Floss says critics of the day warned that because women’s bodies were not designed to go at such high speeds, their uteruses would fly out of their bodies.

Before 1883, there were no national time standards

Cities and towns across the United States set their own times, usually by a public clock in the center of town. The Bureau of Transportation Statistics says that by 1883, there were 144 different local times across the country. This made for great confusion, especially for railroads that needed to schedule train travel. Railroad bigwigs said that in the interests of efficiency, they would divide the continent into four time zones. Thirty years later, the U.S. Congress officially adopted the Eastern, Central, Mountain and Pacific time zones we still use today. The lines between them are at the 75th, 90th, 105th and 115th meridians.

The other reason for coordinating times was safety

As rail traffic increased, trains sharing the same tracks but not the same times would crash into each other. Standardizing times reduced the danger of train-train collisions.

But there were other safety problems

The most dangerous places for pedestrians and the horse-drawn vehicles of the time were where roads and railroad tracks crossed. As trains got bigger, faster, and more plentiful, accidents became more common and something needed to be done about them.

Railroad crossings 

The first warning systems at railroad crossings were simple wooden signs. The X-shaped railroad signs that were invented are called crossbucks and are universally accepted as an indication of danger. The original crossbucks were two equal-length wooden slats with black letters on a white background. The crossbuck sign used a large letter X with “railroad” on one slat and “crossing” on the other. This X design is one of the most universal safety signs in existence to this day.

Today, railroad crossings around the world are marked with an X, but colors and designs vary from country to country

Do you recognize any of the crossbucks above? They are railroad crossing signs from Brazil, Cambodia, Japan, Senegal, and China.


In cities where vehicle and train traffic was heavy, railroad watchmen stood at railroad crossings and waved red flags to warn motorists that a train was coming. Impatient travelers would often ignore the flagmen and cross the tracks anyway.


Bells mounted on poles were activated by sensors in the track. The idea was improved by the addition of wigwags somewhere around 1910. Wigwags were mechanical railroad crossing signals that swung back and forth like pendulums. The waving-back-and-forth motion simulated the waving of red flags to draw attention to the dangerous situation. With the addition of bells, wigwags were the first railroad crossing warning systems to combine sight, motion and sound.


By far the safest way to protect a railroad crossing is with barriers that block the pathways of vehicles and pedestrians from crossing the tracks. The first railroad crossing gates were introduced around 1870 and were hand-operated by railroad employees who turned cranks to move the gates up and down. Gates didn’t begin to be automated until the 1930s when they first accompanied clanging bells and flashing lights.


Flashing red lights were added to indicate danger and quickly replaced the mechanical wigwags. The lights flashed back and forth, simulating the motion of the wigwag. Lights were operated by electric relays wired to the tracks. The first installation appeared in New Jersey in 1913.  

We are all familiar with the warning systems found on today’s level railroad crossings within city limits

Bells start clanging, red warning lights start flashing, and barriers come down to block the traffic lanes. I was surprised to learn that fewer than half of the more than 200,000 railroad crossings in the USA are automated.

Most people are surprised to learn that year after year, more people are killed by trains than planes

Every year in the United States, there are more than 10,000 train accidents at railroad crossings, killing between one and two thousand people. Three out of four railroad accidents occur at crossings without lights and gates, most of them in rural areas. Human error and recklessness account for more accidents than mechanical failures.

The next time you find yourself in traffic waiting at a railroad crossing, Stop, Look and Listen.

Forward this article to a friend for reading next time they’re held up at a train crossing. Then take a minute and reflect on how our signs and signals came to be and how lucky you are to not be one of those who is going to be hit by a train today. 

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Wigwagging is a method of transmitting messages visually by waving a single flag (the use of two flags is called semaphoring). The wigwag system was invented by a physician who once worked with the deaf and ended up as the chief officer of the U.S. Army Signal Corps. This photo is from the October 1961 issue of Boy’s Life, the monthly magazine of the Boy Scouts of America.

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