Stressing

Stressing is a technique developed in the 1960's to avert rail track problems that can occur when installing Continuous Welded Rail (CWR).

When installing new rail the rail must be returned to its former temperature or length.

Technique

In the UK all rail is stressed to 27 degrees celcuis (mean summer rail temperature). Using this figure all rail is stressed to the same value. The most common need to stress is when a piece of rail is removed (a defective rail) or when an IBJ (Insulated Block Joint) is to be replaced. In these cases. The rail is marked and clips removed. The start point of the new rail is then cut. At this point the rail should shrink (a gap is created) due to the stress being lost in the rail. The technician then calculates how much stress is lost and needs replaced. The second cut is made and the old rail removed. The new rail is fitted and welded at one end. A stressing kit is the fitted at the end still to be welded. The kit is clamped to the rail and it pulls the gap together, leaving space for the second weld. Once the rail is stressed to its value the weld is made. After setting the weld the stress kit is removed.

This technique is the basics of most rail stressing jobs. Please feel free to add...

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