Stevenson Valve Gear
In 1841 two employees in Stephenson’s locomotive works, draughtsman William Howe and pattern-maker William Williams, suggested the simple expedient of replacing the gabs with a vertical slotted link, pivoted at both ends to the tips of the eccentric rods.
The valve gear & timing come together real simply. Again, the parts are beautiful. Everything seems to be CNC machining. When I received another section, OS included a letter with replacement parts for the lifting links and rods to correct something they were not pleased with. The letter stated that the replacement was being sent free of charge to customers who had purchased the OS Mogul in the past as an improvement with a more secure taper pin. This show the pride OS takes in their workmanship!