British LMS Stanier Class 5 4-6-0 Locomotive no. 44767 showing experimental Stephenson valve gear unusually mounted outside the framesA simple Stephenson gear in partial cutoff
The Stephenson valve gear or Stephenson link or shifting link[1] is a simple design of valve gear that was widely used throughout the world for various kinds of steam engines. It is named after Robert Stephenson[2] but was invented by his employees.
^Snell, J B (1971). Mechanical Engineering: Railways, Longman & Co, London