What is the maximum allowable length of a rail on which thermite welds can be performed simultaneously on both ends?

The maximum allowable length of a rail on which thermite welds can be performed simultaneously on both ends is 24 feet. This is established to ensure that the welding process maintains proper heat management and control, as well as structural integrity during the thermite reaction.

When welding large sections of rail, simultaneous welding at both ends up to this maximum length helps to equalize thermal expansion and contraction. Exceeding this length could lead to uneven stress distributions and difficulties in maintaining the required temperature profiles, which are critical for achieving high-quality welds. This well-defined limit is in place to provide optimal conditions for the thermite welding process, promoting durability and safety in rail applications.