It would have been helpful if we had been informed what grade of rail was used and what was intended to be used. Since this is as stated, not a safety issue but a wear issue, we would be able to discover what is the difference in performance. Perhaps the existing rails should be used to avoid the delay and waste, then prorate them now for expected life shortfall. Twenty years ago or less, the spec rail might not have existed. The latest premium rails were introduced in 2015. The rails that were used were most likely quite standard in the industry.
Having a friend in the construction business I get to hear stories all the time concerning government projects being designed way over sensible specs and using the same specs for temporary projects. Engineers make bad but well intentioned decisions too. A city wanted to greatly increase the amount of fly ash used in concrete for environmental reasons, right during a fly ash shortage. My friend had to attend a meeting with the engineers to dissuade them from their plan, stating other problems that would result from the idea. He can go into great detail about early concrete tie problems and the fines assessed against Lone Star, resulting from a process issue, not an evil scheme.