It may not look like it has anything to do with railroad history, but this straightedge was one of many surveying tools used by Benjamin Provoost, who was a civil engineer and served as division engineer of the Illinois Central in the 1850s in and around Dubuque.

Provoost helped build the Illinois Central Railroad and oversaw the route that ran from Eldena, Ill. to Dubuque, Iowa. In 1954, he was promoted to chief engineer of Dubuque & Pacific railroad. Provoost later became the director of the Second National Bank in Dubuque.

Straightedges are a useful tool for engineering and can take a variety of forms, including levels, or rulers. Such tools were particularly important in engineering curves in railroad tracks and planning for changes in topography as track is laid to ensure ties are placed correctly.

Basic straightedges are still used today in railroad maintenance, such as checking for abrasion (wearing away) of the metal components of the track. Such abrasion can lead to derailing or rollovers if not repaired properly.