What were the merits of the Southern valve gear vs the Walschaert and Baker valve gears and the Baker vs the Walschaerts?
Why was the Southern use so limited as compared to the commonly used Walschaerts?
[:)]
Several articles in Trains over the years have addressed this and I don’t recall the advantages off the top of my head. Basically one has fewer moving parts. Southern was proprietary to the Southern railroad so others wouldn’t use it and pay them royalties as there was a lot of pride involved.