The Pandrol Head Repair process requires the defect to be ground down leaving how much material above the web section?

In the Pandrol Head Repair process, it is essential to leave a specific amount of material above the web section to ensure the integrity and stability of the repair. Leaving 1/4" of material provides sufficient structural support while also allowing enough material for a solid welding surface during the thermite welding process. This amount strikes a balance between reducing the risk of weakening the overall structure and facilitating effective bonding during the repair, which is critical for the longevity and performance of the rail component.

Excessively grinding down the material could compromise the strength of the repair, while leaving too much material may not allow for an effective weld. Therefore, 1/4" is the optimal thickness to maintain the necessary structural integrity while preparing for the welding procedure.