How much of the melted rail end must be cut off when a rail end begins to melt?

When a rail end begins to melt during the thermite welding process, it is crucial to cut off a specific amount of the melted portion to ensure a proper weld and to remove any imperfections that may have formed. The standard practice dictates removing a 2-inch section of the melted rail end.

This 2-inch cut serves several purposes. Firstly, it eliminates any irregularity or contamination at the melted end, which could interfere with the integrity of the weld. Secondly, it ensures that the surfaces being joined are clean and free from any oxides or other materials that might weaken the joint. Proper preparation is vital for achieving a high-quality weld that can withstand the operational stresses encountered by rail joints.

While the other options represent various cut lengths, the 2-inch specification has been established as optimal for achieving the best possible weld quality in this specific context, balancing efficiency with the need for a clean weld area.