Railtown machinist Robert William’s off-season work on Sierra #28 comes to a dramatic conclusion, as our steam workhorse is returned to operation. This Part III story picks up after most of the bearing refinement has been made, and deals with the complexity of every surprise that Robert discovered along the way, in putting the bearings back in.

First is the test of the floating bushing on the #3 crank pin.
Second, a test of the floating bushing in the side rod.
Third is the wrist pin with the big washer now cleaned and polished up a bit.
In this view, we see the #1 crankpin cap. The outside diameter has just been cleaned up, though outside radius still needs to be cleaned up with a radius tool.
Next, the cap was cleaned up with a Scotch Brite disk, making the original Baldwin “1032E177” code number now much more visible.
In this view, we see the wrist pin nut, on the end of the wrist pin itself.
This view shows us the new jam nuts Robert created for the right side rod bearing strap. These were specifically manufactured so the nuts and bolts on both sides of the engine matched.
Lots of hands are often needed, to move around heavy parts. In this view, we see the crew that has assembled to lift the intermediate rod back into place. L to R: Volunteers Sean Berry-Kelly, Frank Cottle, and Jim Hamilton, and Restoration Specialist Scott Botfield.
Scott applying valve oil on the front knuckle joint bore, in preparation to install the knuckle pin.

While the larger crew was busy with rods in the roundhouse, Jim Hamilton) and Robert Williams were busy in the shop with smaller but important chores so the main rod will go together later that week.

With the main rods still removed, it offered Robert the opportunity to test the wedge bolt and nuts.
In this image we see a tap being used to finish up the internal threads of the new jam nuts.
On the other end of things, we now see the wedge bolt as the thread die is used to clean up some spots where the last jam nuts had caused some distortion of the threads.
This is how the big end of the main rod looks when disconnected from the rod itself, showing the two halves of the main rod bearings that will eventually sandwich the crankpin.
This photo shows the two half brasses now in correct position, with the wedge bolt drawn up and holding the brass halves in the final position. The assembly is now ready for transport to the roundhouse, and its connection to the big end of the main rod.
This is the top of the two halves of the wrist pin brasses, with the oil hole in the middle. The brass on the right needed to be reduced in thickness to match the one on the left.
The new shim to hold the rear brass in correct position with the wrist pin. Here it is still clamped to the angle plate in the milling machine vise.
And now we see the new shim next to the wedge block.
The big end of the main rod strap has been fitted on the crankpin.
On the opposite end of the main rod, we see the wrist pin end, showing the wedge block and the new shim as they fit together.
And here’s how it looks all put together, seen from the back side. Note the back end of the wrist pin in the brasses which insures the correct fit.

Next in Robert’s tasks was to manufacture a new locking key for the eccentric crank arm. A short rectangular piece of metal about 3 inches long with two different widths, the key is custom-fit to the two slightly different width keyways.

A close-up view of the link extension bushing, with evidence of diamond knurl marks from the past that did not work well in the tapered bore of the hole it was meant to fit in.
This is the bushing in the bottom of the link extension, that needed to be replaced.
A drill motor and abrasive flap wheel was used to clean up the bore of the link extension, where the old steel bushing was floating.
Here’s the new bushing in bronze, after the bore was completed.
The new bushing on the left, with outside surface still in the rough, as-delivered condition. The bushing is being test fitted on the pin. On the right is the old steel bushing with oil hole and oil groove.
Here we see the work bench in the Tri-Dam Shop, showing all of the left-side side rods and bearings. Notice also the vertical grey-colored piece of material in the foreground. This is the new 3-inch diameter boring bar for the Bullard Vertical Turret lathe. It replaced the smaller boring bar Robert had to add extra stabilization, earlier. This stronger piece will be used to make up the left side bushings.
This is the wedge block on the left and the wedge draw block on the right. The draw block is threaded internally, and a large diameter bolt is used to pull the wedge tight against the wedge block. This forces the wedge block to keep the wrist pin bushings in contact with the wrist pin. These parts are usually concealed inside the front end of the main rod, and are seldom seen except for major bearing projects like this.
Milling out the inside of the eccentric link bushing.
Looking inside, we see the finished oil groove. There is a second oil groove on the opposite side of the bore to allow oil supply both above and below the pin.

The time had arrived to cool the bushing for the expansion link and press it into a happy new home. Scott made a special trip to secure some dry ice which worked as expected. The bore of the hole was coated with some anti-seize lubricant to insure all went well as the diameter of the bore was not perfectly round.

Some final machining on the bushing, before being chilled with dry ice. The dry ice with just slightly shrink the metal, allowing it to fit into the hole on the end of the expansion link.
Lots of hands working fast with a well-cooled bushing and a big C clamp, to press the bushing into the tail of the expansion link.
Done! The bronze bushing has been fitted into the end of the expansion link, and has warmed up. This allows the bushing to expand in size, ensuring a nice tight fit.
After the bushing is checked for fit, the pin is now inserted and tested for its own fit.
Here is the bushing stock that Railtown staff found in the Warehouse. This was special size just for the needs of the left rear knuckle pin bushing of the #28. The new boring bar was used to finish the bore with some speeds up to 48 RPM. This was a major improvement in speed compared to the former boring bar, which gave trouble at any speed above 12 RPM.
This image shows the inside of the eccentric crank bushing, as the lathe’s live center is used to support the bronze tubing.
The support for the bronze is then changed to a steady rest, as the outside surface is turned to near the finish diameter.
Here we see the backside radius being cut on the #4 crank pin bushing. This was the last of the press-in bushings Robert needed to make.

In an ever-present drive to make things easier and more reliable, Robert decided to apply a new approach to ensure the location of the retainer pin holes in the rod bushings. In the past, this was a real challenge and often times what appeared to be a good alignment of the hole with the pin location in the rod did not align as expected. The decision was made to mark a small groove in perfect alignment with the pin hole.

This image shows the new alignment groove in the #4 bushing. This will be deep enough to show through the frosty surface left by the dry ice treatment.
This is a piece of Starrett Oil Hardening tool steel stock material. It will be cut and milled into a shim to fit the main rod big end brass, where the wedge makes contact.

With the considerable amount of side play in the eccentric rod yokes, it was decided to upgrade the parts with Teflon shims to see what improvements might happen along with the newly installed bronze bushing.

In order to manufacture all of the shims to identical dimensions, Robert secured the three Teflon sheets to a piece of maple with screws, and a piece of birch plywood on top.

First, a pilot hole had to be drilled in the plywood. This photo shows a gauge pin being used, to locate the exact center of the hole.
Next, a wood-cutting bit roughs out the center hole in the shims, and makes room for the boring tool inside
Here is the boring head turning at 1100 RPM, cutting the finish bore on the inside of the shims.
After the screws are removed, Robert now had three identical shims.
Back in the Tri-Dam Shop, we see the left side floating bushing for #3 crankpin.
This is the thrust ring that interacts between the floating bushing and the rest of the parts.
This is the big end strap with both bushing halves now fitted in place. The tool steel shim is in place, as seen by the vertical block of steel now fitting in the forward-facing bushing half.
This image gives a good indication of the sizes of some of the parts that make up steam locomotives. The big end strap, the wrist pin wedge and wedge block in the back of the wagon are ready for a trip from the shop and back down to the roundhouse.
The two halves of the wrist pin brasses.
The wrist pin is test-fitted into the split bushing, and the wedge block and wedge nut fitted to test the alignment of all the parts. At the top we see the white colored waste material that will soon be containing the oil supply for the wrist pin below.
This is the back end of the main rod where the wedge fits. The tapered surface assists with keeping the two big split bushings held tightly together. The surface has been coated with blue layout dye and rubbed with a lapping stone, to give a more desirable surface.
This is the new #4 crank pin jam nut after being given the final facing work in the lathe. Ready for a test fit on the locomotive.

After the parts on the left side were reassembled, the locomotive was now ready for service. By the end of the year, Covid had released its grip on Railtown, and trains were once again allowed to run. Following a few test runs, Sierra #28 was released from the shop, and allowed to once again thrill visitors on board the Sierra Railway.

Although Robert Williams worked as the lead for this project, it is important to note the many other individuals that contributed to these efforts. Volunteers Frank Cottle, Jr. and Jim Hamilton provided many, many hours of valuable hours in machining. Restoration Specialist Scott Botfield oversaw much of the work in placing the parts back into the locomotive, although he also had the help of many others, including Railroad Restoration Specialist Matt Sagaser, volunteers Sean Berry-Kelly, Paul Huston, and many others!