Rail Head Insert for Joint Damage Mitigation
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Solution Overview
Problem
Rail joints experience damage due to discontinuity between rails, particularly in insulated rail joints, leading to detrimental impacts that cause damage to the rails, despite improvements in rail design and maintenance.
Innovation Solution
A railroad rail design featuring a rail head made from rail steel with a void, where an insert made from tool steel or heat-treated A9 tool steel is installed within the void, secured through friction-fitting, force-fitting, adhesive bonding, or brazing, with geometric features to prevent movement and a brazing process using BAg-7 material at 1,200°F to ensure a strong bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rail steel is used for the entire rail head, then the rail structure is simple and easy to manufacture, but the rail ends suffer from damage due to discontinuity impacts in rail joints
Solution Approach 1:
The patent applies composite materials by installing an insert made of tool steel or heat-treated A9 tool steel (hardness 49 Rc or 462 BHN) into a void in the rail head made of rail steel (hardness 380 BHN). This composite structure combines the toughness of rail steel with the hardness and wear resistance of tool steel, specifically addressing the rail end damage problem in joints while maintaining overall structural integrity.
Solution Approach 2:
The patent applies local quality by concentrating the harder insert material specifically at the rail head end where discontinuity impacts occur in joints. The insert is positioned to receive the impact forces at the rail end, while the rest of the rail head maintains its original rail steel composition. This localized application of different material properties addresses the specific problem area without unnecessarily complicating the entire rail structure.
2Strength
If a void is created in the rail head to accommodate the insert, then the rail end damage is reduced through harder insert material, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-forming the void in the rail head during the rail manufacturing process, before the rail is installed in the track. The void is created as part of the initial rail fabrication, and the insert is then installed in the field or at a maintenance facility. This approach separates the complex void creation from track maintenance operations, making the overall process more manageable.
Solution Approach 2:
The patent applies the intermediary principle by using a bonding agent or adhesive material to secure the insert within the void. This intermediary substance facilitates the connection between the insert and the rail head, ensuring the insert remains firmly in place to withstand impact forces while allowing for a relatively simple installation process.
3Ease of manufacture
If the insert is secured using friction-fitting or force-fitting methods, then the installation process is simplified, but the bond strength may be insufficient to withstand impact forces
Solution Approach 1:
The patent applies parameter changes by specifying precise geometric parameters for the void and insert interface, including complementary geometrical features that enhance the friction-fitting or force-fitting connection. The void is shaped to provide optimal mechanical interlocking with the insert, and the bonding surface areas are designed to maximize the effectiveness of the chosen installation method while maintaining adequate bond strength.
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
The solution effectively reduces rail end damage by enhancing the durability and performance of rail joints, particularly in insulated and standard rail joints, by utilizing a harder insert material to mitigate the impact of discontinuity and improve the bonding process, thereby extending the lifespan of rail infrastructure.
Implementation Method 1
heating the wrapped insert and surrounding rail head to braze the insert to the rail head
Data Source
AI summary
A railroad rail comprising a rail head, wherein the rail head is made from a first material and defines a void, and an insert comprising a second material installed in the void.