Adzing of sleepers. The sleepers are cut at the rail seat to provide a slope of 1 in 20 to the rails. The process of cutting the wooden sleepers or casting of concrete sleepers accordingly is known as adzing of sleepers.

Sleeper adzing is a traditional railway maintenance process used to create a flat, smooth surface on a wooden railroad tie (known as a "sleeper" in the UK and Australia) where the steel rail seat or baseplate will rest. The term comes from the "adze," a tool similar to an axe but with a blade set at right angles to the handle. Historically, workers would manually adze the wood to ensure the rail sat perfectly level and at the correct "cant" or angle. In 2026, this process is almost entirely automated by heavy machinery known as "sleeper adzing and boring machines." These machines not only plane the wood to a precise finish but also drill the holes for the spikes or bolts simultaneously. This is a critical step in track longevity, as an uneven surface would cause the rail to vibrate or "chew" into the wood, leading to premature rot and potentially dangerous track misalignments. By ensuring a perfect fit, adzing helps maintain the structural integrity of the rail bed.