Book 3, Question 6 · Video
Why Do Trains Need Tracks?
A train wheel is steel, and the rail is steel too. Smooth steel rolling on steel has very little rub, so heavy trains can roll easily. And the tracks show the train exactly where t
Read the full answer →What Crafty Clover says in this video
Intro
Hey there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why do trains need tracks?
The Big Idea
A train wheel is steel, and the rail is steel too. Smooth steel rolling on steel has very little rub, so heavy trains can roll easily. And the tracks show the train exactly where to go! Thousands of tons of train can move this way!
Step 1
Step one: a steel wheel on a steel rail. Smooth steel touching smooth steel makes very little rubbing. That's why one train can roll a long way with less effort. Trains can be very long and very heavy, yet they still roll along smoothly.
Step 2
Step two: the flange hugs the rail. The flange is a lip on the inside edge of each wheel. It hugs the rail and keeps the wheel from sliding off the track. Because the flange never lets go, the train keeps following the curve of the track.
Step 3
Step three: the track sets the path. Where the rails go, the train goes. So even a very heavy load can move safely along its route. Trains use switches, which are special track pieces, to change from one track to another.
A Closer Look
Let's take a closer look at a train wheel and rail! The flange is the lip that hugs the rail. The tread is the flat part that rolls on top of the rail. And the rail sits on ties, which hold the track in place. The wheel and the rail work together!
Quick Facts
Quick facts! Steel on steel is slippery, but in a good way, because it rolls so easily. Tracks are laid a fixed distance apart. That distance is called the gauge. A derailment happens if the wheel climbs off the rail. Grown-ups called inspectors check the tracks to keep everyone safe.
Think Like a Scientist
Now, think like a scientist! First, roll a toy car across a carpet. Next, roll it along a smooth ruler. Which one goes farther, and why do you think so? Notice how much less rubbing the smooth path has! Smooth surfaces are great for rolling, and rough ones slow things down.
Outro
Smooth steel wheels and rails make heavy trains roll. Train science is on track! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!