Michigan Compiled Laws, Chapter 205. Taxation § 205.54m

Sec. 4m.A sale of rail freight or passenger cars, locomotives or other rolling stock, roadway machines and work equipment primarily of a flanged wheel nature, accessories, attachments including parts and materials used for repair, lubricants, or fuel, used in rail operations is exempt from the tax under this act. This exemption does not include vehicles licensed and titled for use on public highways.