Hello.
 I have been wondering about this for awhile. I tried looking this up but found very little. What was the performance increase after the conversion to Belpair firebox if any. What was the costs per unit to convert? Was there an increase of weight on drivers and tractive effort? Did it matter which valve gear and was there a difference in performance between the Southern and Walschaerts? Is there any test plant documentation?
       Thank You.
      Pete