The French national railway company Société nationale des chemins de fer français (SNCF) was created from the merger of five private operators in 1937. Coinciding with that amalgamation, a new logo was introduced as well. The depicted roundel was designed by Maximilien Vox and purposefully made use of entangled letters to depict the former stand-alone companies now forming a new whole. The extra large letter C gives the logo the necessary visual structure and balance.
Even though the roundel was only in official use for 10 years, with a new crest being introduced in 1947 and replaced by other variants in subsequent decades, Vox's original SNCF logo remains the most famous and instantly recognizible of the lot. The red and white SNCF roundel continues to grace preserved steam, diesel and electric locomotives that were built during the middle of the 20th century, be they static exhibits in museums or operational vehicles on the main line.