January 31, 2009

Progress on frame

While the cylinder-saddle is the most prominent feature of the frame, there are many elements of the frame restoration that are being worked on in parallel.  Below are photographs of several of these projects, including:

Box hangers for the spring rigging
Valve gear links
Driving boxes (replacement boxes are being cast & will be machined)
Smoke box inside liner
Buffer/chaffing block

One heavily worn area is the stationary chaffing block portion of the buffer located at the back end of the locomotive frame, between the locomotive and tender. The buffer assembly is a spring loaded device mounted on the tender that keeps the locomotive snug against the tender and allows the locomotive and tender to negotiate curves. When maintained to the specific design  this device reduces surging from piston thrust that can be felt in the cab and the train. This piston thrust, if uncontrolled at this point, places great strain on the drawbar which connects the locomotive and tender causing excessive wear on the drawbar and the pins that secure it .

On the tender, there is a spring pocket which has a mating surface on the locomotive called the stationary chaffing block.

Earlier photos document that there had been attempts to "repair" this area by stacking and welding a series of shims to form a makeshift radius. These welded shims were loose, heavily worn to a shelled out condition and had broken welds.

Procedures were developed to repair the casting which is attached to the back of the locomotive frame at the drawbar center casting by machining a steel block to the correct radius, machining the old casting flat at the mating surface, securing the radius repair block with fasteners to the original casting, seal welding the block to the casting and blending the welded area between the new block and the casting to the correct radius. After this process, the  repaired casting will be sent out for stress relief to reduce cracking potential at the welds.

Steel block being CNC machined for the new buffer radius. The new radius piece will be bolted, welded and stress relieved after application to the buffer casting.	Photo: Steam Operations Corporation
New buffer radius prior to attaching to casting.	Photo: Steam Operations Corporation
New driving boxes are being cast.  (The original driving boxes had cracks and it was determined they should be replaced.) For the four axles, 6 of the 8 driving boxes are the same size.  Currently, 2 are complete and ready for machining, 2 are being stress relieved and 2 remain to be cast.  The remaining 2 main driving boxes are larger and require a different pattern.  They should follow in about a month. The driving boxes are also being fitted with a newer pressure lubrication system that will allow a greater degree of serviceability for the foreseeable future.	Photo: Steam Operations Corporation
Left and right bottom sections of new smoke box.  Plate steel availability in the size required made it necessary to form the smoke box in two sections. The rolled sections will be welded together.	Photo: Steam Operations Corporation
Smoke box inside liner during forming process.  The half moon pieces will keep the diameter constant at the 86 inches while being fit to the original upper portion of the smoke box. Final assembly photos will show more detail of this process   The bottom of the smoke box requires a liner of equal thickness to the smoke box proper, in this case 1/2 inch thick. This increases the strength of the structural assembly at the fit of the cylinder saddle. It is in this area that the taper fitted bolts are applied to secure the smoke box to the saddle	Photo: Steam Operations Corporation
Crane lifts smoke box bottom section on to new saddle fit for a test fit.	Photo: Ronnie Jones LTMC/SOC
New smoke box bottom section test fit on saddle showing  correct rolled fit of plate to saddle radius.	Photo: Ronnie Jones LTMC/SOC
Ronnie and Tyler discuss measurements on trailing truck transverse equalizer.	Photo: Steam Operations Corporation
Frame liners at spring rigging transverse equalizer showing heavy wear on inside lateral surfaces.	Photo: Steam Operations Corporation
Valve gear link hanger mounted in frame to measure offset of valve centerline to centerline of link. Bushings in frame are loose and worn.	Photo: Steam Operations Corporation
Wire represents valve centerline used to find center of link and link block.	Photo: Steam Operations Corporation
Box hanger  for spring rigging after welding and machining to restore radius for spring clip fit. Once all box hangers are repaired they will be stress relieved.	Photo: Steam Operations Corporation
Box hangers showing typical heavy wear.	Photo: Steam Operations Corporation