Not All Frogs Are Created Equal

Some are green, and some are brown. You might see one in your backyard or even one on Sesame Street. But many people might not realize when they come across a frog on a railroad! 

What is a rail frog, you may ask? It’s a major component of a minor but frequent occurrence on the railroad. On every railway, a train will eventually reach an intersection and cross over the rail of a diverging track, known as a switch or turnout. A frog is the device that allows this switch or, as the rest of the English-speaking world refers to it, crossing.

Contrary to what most believe, a rail frog is not named after the amphibious creature it resembles in name, but instead after the frog of a horse’s hoof. This type of frog is shaped in a “V” and acts as a shock absorber for when a horse’s foot makes impact with the ground. It is also an important part of a horse’s circulatory system – pumping blood into the leg each time it contacts the ground. 

In our industry, rail frogs enable the wheels running on one track to switch or cross onto another. On every wheel there is a flange - the protective edge or rim on the circumference of a railcar wheel, that helps steer train wheels. 

When the train comes to a crossing with another track, there is a gap in the frog that allows the flange to cross an adjacent track. 

Like their amphibious counterparts, rail frogs are found in a few different places, such as diamonds or crossings where trains can’t easily change paths. 

High-quality rail frogs ensure that the train transfers smoothly between rail lines, while defective or subpar frogs can jeopardize the safety of the switch, wheels and railcar or even shut down the railroad. 

Just as there are many different types of living frogs, there are many different classifications of rail frogs, based on how they are produced. The most common material used is manganese steel. This new material is made by re-alloying high manganese steel with elements such as copper, vanadium and titanium. 
If you are interested in learning more, contact Bonnie Hatfield at, who can link you to your local roadmaster.