Which is : Machinery will operate as long as there are people around to care for and repair that machinery . Twentieth Century locomotive manufacturers told customers that the locomotives they erected and delivered had a thirty year life span . Buyers knew they could keep power going longer if they maintained them . Some engines we are familiar with have plenty of years left in them .Class K-36s are perhaps the most complete of all remaining steam classes in the world ,with 9 of the 10 in existence , and 8 of them serviceable or awaiting repair . Their boilers are in very good shape ,though all of them are probably on their second firebox. The 470s are all on their third firebox .Smaller engines seem to develop more firebox problems ,possibly because they combust their fires quicker and experience more heat and pressure fluctuations . Also the boiler barrels of the 470s may be thinning . I remember they could barely hold a belly plug ,as the boiler plate seemed thin down there. So down the road they will need new boilers ,but that is not impossible to do ,just very labor-intensive and expensive . There is also the possibility that the 470s simply need patches ,like #463 received when Bush rebuilt the engine in 1994. I believe the Ffestiniog in Wales built a new Fairlie-type engine a few years back with all the latest in design improvements . Unfortunately some engines , due to poor maintenance and inappropriate use end up completely worn out .RGS #42 may be nothing more than a display engine . With its frame broken in six places and a thoroughly worn out boiler ,it is good for little more than a template for a new engine .
