Rail Head Defect Repair via Interference Fit Steel Plug
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Solution Overview
Problem
Existing methods for repairing mechanical defects in rail tracks, such as squats, often require significant disruption to the rail geometry and may not maintain the original operational state, especially when dealing with defects that occur over time due to train traffic, and may not ensure a durable and corrosion-resistant fixation without auxiliary materials.
Innovation Solution
A method involving the removal of a piece from the rail head's upper surface to create a hole, which is then filled with a prefabricated, shape-retaining steel plug that is permanently fixed through interference fit, allowing the rail to maintain its original geometry and operational state, using a process that involves cooling the plug to fit snugly into the hole and utilizing the train's wheel pressure for cold plastic deformation to secure it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a wedge-shaped piece is removed from the rail and filled with a prefabricated plug, then the rail geometry is restored, but the rail web and lower part of the rail head are affected and require significant disruption
Solution Approach 1:
The invention segments the repair process by removing only the defective portion (squat) from the rail head while leaving the rail web and lower parts intact. This is achieved by drilling a hole through the defect and removing material only from the affected area, rather than removing a large wedge-shaped piece that would disrupt the entire rail structure.
Solution Approach 2:
The repair method applies local quality by treating only the specific defective area (the squat) with a plug, while preserving the original rail structure elsewhere. The plug is inserted into a precisely drilled hole at the location of the defect, restoring the local geometry without affecting the overall rail web and foot structure.
2Ease of manufacture
If a prefabricated plug is used to fill the hole, then the repair is simplified, but auxiliary materials like adhesives or molten steel are required for fixation
Solution Approach 1:
The plug is designed to secure itself within the drilled hole through its own structural properties. The plug features a conical shape that matches the tapered hole, allowing it to be inserted and secured without requiring auxiliary materials such as adhesives, molten steel, or additional fastening components. The plug's geometry enables it to wedge itself firmly into place.
3Reliability
If the plug is permanently welded to the surrounding rail, then the fixation is durable, but the process becomes complex and requires auxiliary materials
Solution Approach 1:
The invention replaces the welding process (thermal/mechanical system) with a purely mechanical interference fit system. The plug's conical shape creates a wedge effect that generates friction and mechanical interlocking forces, securing the plug firmly in the hole without requiring heat, electricity, or chemical bonding agents. This substitution eliminates the complexity of welding equipment and procedures.
4Ease of repair
If the upper surface of the rail head is removed to access the defect, then the defect can be repaired, but the original operational state and geometry are compromised
Solution Approach 1:
Instead of removing material from the upper surface to access the defect (which would compromise the running surface), the method inverts the approach by drilling the access hole from the upper surface through the defect and then removing the loosened material. The plug is then inserted from the same upper surface opening, restoring the original geometry without permanently compromising the rail's operational surface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for in situ repair of rail defects without affecting the rail web and foot, ensuring a durable and corrosion-resistant fixation, maintaining the rail's original geometry and operational state, and eliminating the need for auxiliary materials like adhesives or molten steel, thus enabling quick and effective restoration of the rail's surface for continued safe train traffic.
Implementation Method 1
using a process that involves cooling the plug to fit snugly into the hole
Implementation Method 2
utilizing the train's wheel pressure for cold plastic deformation to secure it
Implementation Method 3
ensuring a durable and corrosion-resistant fixation
Data Source
Figure 1~3
Figure 4~6
AI summary
A method of in situ repairing of a defect (15) in a rail (10) which comprises removing a piece of rail head (14) from the upper face of the rail head so that the rail web (13) and the rail foot (12), and optionally the lower part of the rail head (14) remain unaffected, so that in the rail head a recess, preferably a hole (20) is formed, whrein the recess debouches at its upper face, and teh method further comprises the filling of the recess (20) with a preformed, shape-retaining, preferably closely fitting, steel plug (21), the shape of the recess (20) and of the plug (21) being congruent in order to restore the original geometry of the rail.