Why 32 shades of green caused serious problems – and how glass scientists changed it all

Rail travel transformed the U.S. economy more than 100 years ago. But the young cross-country rail system was also extremely dangerous. Early glass lanterns were woefully incapable of alerting engineers to potential hazards at crossings.

First, the lanterns quickly collected dirt, which weakened the signal considerably. An innovative new design helped solve that issue. But color inconsistency remained a major problem.

How could red mean “stop” or green mean “go” when there were so many shades being used by different rail companies? What colors would be most luminous, even in blinding snow, while still maintaining durability?

Innovative glass scientists solved the problem – and created a standard look for safety signals that remains to this day.

How? Find out here.