Why Railroads Don't Need Expansion Joints

Summary by Krater

This video explains the engineering mechanics of continuous welded rail (CWR) and why jointed rails are no longer common due to thermal expansion, buckling, and maintenance costs.

From the video

Answers: Why do modern railroads use continuous welded rail instead of jointed rails?

• Continuous welded rail
• Thermal expansion in rail
• Buckling and sun kinks
• Railway track maintenance
• Stress and strain in materials

What it concludes

• Continuous welded rail eliminates most joints, greatly reducing maintenance costs and the clicketty-clack noise.
• Without thermal expansion joints, temperature changes create high compressive and tensile stresses within the steel rail.
• Restraining the rail prevents thermal expansion, resulting in compressive stress that can cause buckling or sun kinks on hot days.
• Railroads use high neutral temperatures during installation to ensure rails rarely undergo compression.
• Ballast and rail anchors provide essential resistance to hold rails in place and prevent lateral buckling.