This document summarizes information about welded railway tracks from a textbook chapter. It introduces welded joints and long welded rails (LWR) as ways to reduce the number of weak rail joints. LWR terminology like "breathing length" is defined. Continuous welded rails (CWR) that have no joints at all are also discussed. Theories for how LWR works are presented, including equations for calculating the force and amount of expansion/contraction based on factors like the coefficient of linear thermal expansion, modulus of elasticity, and breathing length of the rail. An example problem is referenced from the textbook.

1. Dr. Walied A. Elsaigh
welsaigh@ksu.edu.sa
Asst. Prof. of Civil Engineering
Jumada’-I 1437H
CE 435
Railway Engineering
Welded
Railway Tracks

2. Text Book
Railway Engineering,
Satish and Agarwal,
2nd edition, 2013
Chapter 8
Page 324-342

3. Introduction
Rail joints are the weakest links in the railway track
Railway track with joints requires 30% extra maintenance.
Reduce the number of joints
(Use longer rails – KSA = 30 m)
Use welded joints

4. Long Welded Rails (LWR)
Terminologies
Breathing Length:
is the length at each end of an LWR
that is subjected to expansion and
contraction on account of variations
in temperature.

5. Continuous Welded Rails (CWR)
Terminologies Gaining popularity ,
Developing rapidly in
the past few years
No Joints at all
(joistless).
So how it works?
KSA?
LWR or CWR
No expansion
or contraction.
Rail section is large enough to
take internal stresses due to
expansion and contraction

6. Theory of LWR
P = Force
A = cross-sectional area
α = coefficient of linear thermal expansion (1152x10-8 per degree Celsius)
E = modulus of elasticity of rails (2.15x106 kg/cm2)

7. Cont. Theory of LWR
δl= amount of expansion or contraction
l = the breathing length of the rail

8. Cont. Theory of LWR
Example 17.1 page 327 textbook