Page 161 - Handbook of Materials Failure Analysis

7 Conclusion 157

1200
y = 3.9967x
Sleeper/ballast contact pressure (kPa) 800
2
R = 0.9998
1000

600

400

200

0
0 50 100 150 200 250 300
Rail seat load (kN)
FIGURE 6.29
Relation of forces and reactions using contemporary methods of analysis.

Table 6.6 Estimate Costs Associated with Turnout Renewal Due to
Systemic Failure
Renewal % Cost
Items Cost ($) component
Materials 200,000 6.2
Machinery 75,000 2.3
Access/possession fee 50,000 1.6
Human resources and labors 150,000 4.7
Commission and signaling 100,000 3.1
Re-design, manufacturing 50,000 1.5
Formation improvement 100,000 3.1
Others (train replacement busses, logistics, delay costs, >2,500,000 77.5
penalty fees, opportunity costs, etc.)
Total >3,225,000 100

7 CONCLUSION
Concrete sleepers/bearers are the main components supporting steel works and redis-
tributing dynamic forces onto ballast and formation. Because of their low cost, high
durability, ease in construction, and maintenance, concrete bearers will continue to
be the popular components in modern turnout systems. However, wheel-rail contact
over the crossing transfer zone has a dip-like shape and can often cause detrimental