Train wheels can now be more out-of-round, making maintenance cheaper

US rail regulators are proposing to allow a wider variation in the diameter of train wheels. This means train operators will not have to replace or repair wheels as often, especially on newer electric locomotives.

For decades, rules about train wheel diameters were based on older diesel technology. Newer electric locomotives handle wheel wear differently. This change means operators can run trains longer before needing maintenance, which saves money and keeps more trains in service. It also acknowledges that modern traction control systems can compensate for slight differences in wheel size.