Why Don’t Railroads Need Expansion Joints?

How Thermite turned the clickety-clack of railroads into seamless, silent tracks. Get an exclusive 15% discount on Saily data plans! Use code veritasium at checkout. Download Saily app or go to https://saily.com/veritasium A massive thank you to everyone at Goldschmidt for making this possible. With special thanks to Dr. Axel Hoeschen, Christof Gassmann and Claudia Koch.

If you want to learn all the details about why we don’t need expansion joints anymore, check out Grady’s excellent video here: youtu.be/zqmOSMAtadc

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▀▀▀ 00:00 The problem with continuous welded rail 03:33 How to weld two rails together 10:16 Why is rapidly cooled steel brittle? 11:40 Thermite reaction and a see-through mould 16:30 Clean up 19:11 Metallurgy 22:15 How strong is the weld? 24:26 Why don’t the rails buckle?

▀▀▀ References: Practical Engineering. Why Railroads Don't Need Expansion Joints youtu.be/zqmOSMAtadc Stress–strain curve In Wikipedia - https://ve42.co/stressstrain The Efficient Engineer. Understanding Metals via Youtube https://youtu.be/PaGJwOPg2kU moodlemech. Properties and Grain Structure via Youtube - youtu.be/uG35D_euM-0

Images & Video: bhadeshi123. Martensitic transformation via Youtube youtu.be/OQ5lVjYssko Stratford Works In Wikipedia - https://ve42.co/stratford Electric Tram 1881 In Wikipedia - https://ve42.co/tram Water Quenched Steel In Wikipedia - https://ve42.co/quench Synagoge 1922 In Wikipedia - https://ve42.co/synagoge

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