In addition to what Dusty has said I will add this. 318 should have 3/8" thick interior firebox sheets. Currently her firebox is 1/2" thick. The "story" I have been told is someone thought if 3/8" is good, 1/2" must be better. Not true in this case, and as has been pointed out thicker material takes longer to heat up. It is truly heart breaking as the work that was done on the firebox is really nice.
That being said 318 also needs a front tube sheet, a new dry pipe and possibly some steam dome repairs. Also remember she was derated to 145psi by the Rio Grande, so less power than 315, 346, and RGS 20.
Lastly I believe it was 1978-1979 that 318 was under steam at CRRM. She developed firebox issues and was taken out of service. The plan was always to rebuild her and return her to service. Lots of other work was done to 318 besides the firebox. But the plan changed, and we have no current plans to get her operarional.
On the positive side we finished our rebuild of the right side cab wall. We also took the time to add some items that were not there or had been removed and freshen up some of the paint. 318 is back out on display. In a few years we will bring her back to the shop and replace the rest of the cab, repair the tender and repaint both. If folks donate to the cause it could happen sooner.
Jeff Taylor
CRRM curator of equipment and rolling stock.