How does train bogie/ coach travel in curve

1.The wheels on each side of a train car are connected with a metal rod called an axle. This axle keeps the two train wheels moving together, both turning at the same speed when the train is moving. ... This is where the wheels' geometry comes in. To help the wheels stay on the track their shape is usually slightly conical.
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2.The only part of a train wheel that actually touches the rail is around the size of a 10 cent/20pence coin. Think about that the next time you're hurtling along at 130Kph. Actually - the wheel flange very rarely touches the rail. What keeps the train on the track is the conical angle of the wheel profile.
3. Why do trains not derail?
the reason these trains never tip is also because of their conical wheels. The conical wheels' shape, every time the train tips, the amount that it tips acts to restore the train upright. This force, called a restoring force, is stronger when the train is heavier meaning heavier trains are more stable .
Source - science journal