The Midland Railway 115 Class was the third of four classes of 4-2-2 steam locomotive, nicknamed "Spinners", designed by Samuel Waite Johnson. A total of 15 of the class were built between 1896 and 1899. They were capable of reaching speeds of up to 90 miles per hour.

It was quite common for engines of this class to pull a typical Midland express, which suited the Class 115 perfectly. Given a dry rail they could maintain a tight schedule. Speeds up to 90 mph were not uncommon, and the sight of their large, spinning driving wheels with no visible connecting rods, like a spinning wheel, earned them the nickname "Spinners". Thanks to the Midland's practice of building low powered locomotives and relying on double-heading to cope with heavier trains, many enjoyed working lives of up to 30 years. 

15 were built, and one engine, No. 673, is preserved in the National Collection.