RGS 20 Pix 12 Sep 2008

All the shell patches are in and the xrays were done last evening and everything is good. This is good news since there was some concern about an area on the left side of the backhead through which the weld ran. The pictures of the old steel were satisfactory.

The next step is to make the braces and get them installed. We discovered that the t-irons dictated a different location for the shell feet. Relocating the shell feet will solve the interference problem certain braces had with crown bolts. The old feet will be reused and moved to the new locations. At this time we do not know why the braces were located where they were. One brace needs to be bigger in diameter than the original in order to stay under the 9000 psi stress limit.

While the braces are being built, the doublers will be applied to the throat, backhead, and side wrappers. The doublers will be applied with fillet welds on the doubler perimeter and inside the enlarged clearance holes for the staybolts. The support studs for the firebox carriers can be welded or threaded with this type of doubler installation. We will probably choose welding as it does not compromise the shell. The old doubler on the right side wrapper will be removed and the stay holes enlarged to clear the bolts and allow for the fillet weld without interfering with the stays. In the original construction the stays were part of the attachment for the doubler but in so doing it effectively shortens the stay by the thickness of the doubler which causes more bending and higher stresses on the bolts and the sheet.

The entire wrapper will be fillet welded to the mudring. You can see where that weld is in place on the backhead and throat. Additionally the driver clearance patches common to narrow gage locos will be fillet welded on the inside prior to the firebox being installed.

The side wrapper to throat and side to backhead rivets near the mudring are tall enough to impede circulation. Removing these and making countersunk rivets inside and out would make a better job so we may do that in addition to double fillet welding the joint. The only hesitation is that this area shows no signs of problems and sometimes if it ain't broke don't fix it. The flip side is that the door sheet was severely grooved in the corners which may have been caused in part by the circulation interference caused by the rivet heads. This decision will be made when we do the final fit of the rear flue sheet and door sheet.


Cut out for throat patch and stay hole repairs


Cut out for throat patch and stay hole repairs


First fit of throat patch


Inside view of final throat patch installation


Outside view of throat patch completed


Making the side wrapper patch


Installing side wrapper patch


Completed side wrapper patch


Completed side wrapper patch inside view


Backhead patch installation


Completed backhead patch inside view


Completed backhead patch outside view


Brendan drilling holes for new placement of brace feet


New rear flue sheet after water jet cutting