Think of a pearl necklace. Pull the necklace along by the first bead. The rest of the beads follow. Replace the first bead by a powerful engine. Replace the rest of the beads by light passenger cars.

Think of the passenger cars being pulled by the engine around a curve at 106 miles an hour. Suddenly the engine puts on the brakes and the cars start banging together and like the pearl necklace, the cars are
pushed” to the outside of the curve and off the track. pulling and starts pushing the cars backwards. The cars in the middle would curve outwards and jump off the track. Try it with a necklace. Form the necklace into a curve a push the first bead. Watch what happens to the rest of the beads. They bend to the outside of the circle.

How many trains went around that curve at 106 miles and hour or faster? Most likely lots of them but for right now, no one’s talking. None of the trains derailed. Why not? Because none of them slammed on the brakes while the train was being pulled around the curve.

When a train is being pulled around a curve the cars are being pulled by the power of the engine and they are going around the curve because the flanges on the wheels and the track are providing the force needed to make the cars follow the curve. The power of the engine is being used to help the flanges and the track to turn the train as it goes around the curve. The power is pulling the cars towards the inside of the radius of the track. The engine pulls the first car which pulls the second car which pulls the third car. When the engine is in the middle of the curve it’s pulling the first car straight ahead but the track and the flanges are making the car turn. When the brakes are applied, the prakes on the engine are far more powerful than the brakes on the cars because the engine weighs far more than the cars. So the brakes on the engine will actually “push” te first car a bit which will “push” the second car a bit which will push the third car ans so on which “push” will push the following cars a bit to the outside of the curve. If the “push” force is sufficient to slow down the entire train the middle and read cars will go off the track, just like pushing a pearl necklace. The wrong thing to do is apply hard braking when the train is going around the curve.

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