Hallade was not alone.

His method of track alignment rectification is by far the most used and known but there are quite few other methods for rectification and even proper realignment.

One of these methods used a strange curve called involute (or evolvent). It was first described in this book from 1927.

Die Absteckung von Gleisbogen aus Evolventenunterschieden (Realignment of track curves from involute differences)