Dan ,Replacing the "Jewelry" as you well know is extraordinarily expensive . Injectors can cost $4000-6000 apiece and lubricators ,gauges generators ,air pump parts etc. also add up . Those older engines had assembled frames ,and they suffered more problems with breaking than cast frames .The good news is according to my Uintah book the #12 received an extra-order boiler from Baldwin in 1924 . Since the engine was limited to use between Mack and Atchee ,and was a reserve engine to the 2-8-2 #40(the only inside frame 2-8-2 in Colorado),it saw very little use .To my understanding it only ran a year on the EN .So the boiler has only 14 years real-time use .The variables are this : The country it ran in was stratified rock ,known for very bad water .How good the boiler shell also depends on whether the EN properly drained the engine . The 1896 boilers were recognized by the D&RGW to have problems and the boiler pressure was only 140psi,the lowest on any "modern" D&RGW engines . Also ,those engines were sidetracked because of boiler problems ,like #316 and #317 .The failure of the #318's boiler has kept that engine on blocks for years at the Colorado Rail Museum . Theoretically ,the #12 might have the best boiler of the three remaining of its type . Is there any interest in running it again ?