“As the Parts Turn” or “How It All Goes Back Together”


The steam fountain on this 1922 Baldwin steam locomotive is a cast steel manifold that distributes steam to accessories and appliances such as the air compressor and injectors. It is located on top of the locomotive boiler inside the cab.   It is the main fixture for the distribution of steam to all of the appliances except the lubricator. (The lubricator has its own dedicated steam source.)  The fountain gets its supply of steam through a pipe that runs all the way into the steam dome.  The Turret Valve is the main “stop valve” that is used to shut off all of the steam flowing into the fountain in case of a steam leak or failure.  Early locomotives do not have this valve.
All of the valves on the fountain are typically closed or open. The valves include – two injector valves for the Monitor lifting injectors, an air compressor valve, the dynamo valve, the steam heat valve and a valve that supplies steam to the fireman’s manifold.  The air compressor valve was made by The Westinghouse Air Brake Company; the injector valves, firing manifold valve and lubricator supply valves are original valves made by the Baldwin Locomotive Works and have been on this locomotive since 1922.  This 95-year-old locomotive is amazingly original.

fig 1 turret diagram

Sierra No. 28’s Historic Steam Fountain

The image above shows the fountain when it was removed from No. 28 last year. The original firing manifold valve was removed in 1992 when it failed and was replaced with a contemporary Lunkenheimer steam valve.  It is quite common with historic locomotives that are operating to make field modifications that keep the engine running but may not be historically accurate. Twenty five years ago, the worn valve was put away in the parts warehouse in the valve bin. This valve was located and was rehabilitated by volunteer machinist Robert Williams. It will be put back in its historically correct location getting the No. 28 that much closer to how it would have looked back in the 1920s.
The type of valve that best describes the ones used on the fountain is the globe valve, seen below.

fig 2 globe valve

The valve stem or spindle (E) is located in the center. It is the bronze rod with the red handle on it. The stem is held in place by the valve body (G) and the bonnet(C). The bonnet also holds the packing nut (F) in place over the stem. This packing nut along with the packing bushing hidden underneath the packing nut (F) (not shown in this image) keeps the steam from escaping up the stem.  When the packing nut is tightened, pressure is applied evenly to the top of the packing bushing which then compresses the packing on the stem creating a steam tight seal.   The union nut (B) holds the bonnet in place. The threads on the valve stem allow the sealing disc (D) to travel into the seat (A) or away from the seat (valve in the open position) when the handle is turned.   This diagram shows the valve in the open position. A top nut (H) secures the handle to the stem/spindle.

fig 5 valve removed and on the benchFig 4 valve refurb

fig 3 a valve refub

A succession of images showing the turret valve’s transformational refurbishment. 

The work on the valves at the fountain is extremely specialized; as with most parts on a steam locomotive, there are no part numbers and no technical support.
All of the fountain valves needed attention.  Most stems/spindles were completely worn out allowing a lot of play- some almost to the point of thread failure.  We ordered C464 bronze stock and volunteer Robert Williams fashioned completely new valve stems for these two valves. Since the stems were very worn, and the internal threads in the bonnet were somewhat less so, Robert used reverse engineering (and some guesswork) to sneak up on the exact dimension and make a perfect fit between the internal threads of the bonnets and the new spindles.

fig 6 Jamestown steam valve square taper

New and old spindles

The two identical appearing injector valves gave us a big surprise when it was discovered that one is a 6 pitch (threads per inch) Acme thread and the other is a 5 pitch.  We are still wondering if they came from Baldwin that way.  For more information on Acme threads click here. https://en.wikipedia.org/wiki/Trapezoidal_thread_forms

All of the packing bushings in these globe valves were found to be in poor condition so all new packing bushings were made to fit the needs of each valve.  At the request of George, Robert included a custom lip on the top of each new packing bushing which will make servicing the packing in the future much easier.


The nuts that secure the handles to the top of the stem/spindle, was also of dubious quality with no common design between any of them.  It was easier to start fresh with stainless steel hex stock and make tall heavy style hex nuts that will complement the entire set of rebuilt valves and look great for the next century.  A custom “washer cut” was made on the nuts while in the lathe so the bottom of each nut will never need a flat washer in service.
The turret valve had a much-corroded seat.  Our gracious volunteer machinist used a 3 ½ “valve seat cutter to recut the turret valve seat to perfection, removing almost a century of pit corrosion that looked like Swiss cheese.turret vavle seat set up diagram

Fig 9 removing corroded seat

The 3 1/2 inch seat cutter dressing up the turret valve seat in the milling machine

fig 10 old vavle stems

Nearly a century old, the valve stems removed from the various fountain valves were worn, some very worn. 

fig 11 valves lined up on machine

Vavles awaiting complete overhaul


Here are the refurbished valves that will be installed on the fountain. 


Locomotive No.28- Putting All the Bits Back On

After getting the boiler water tight and completing the hydrostatic testing, everything that was taken apart begins to come back together. All of the items removed from the locomotive for access to the boiler were closely inspected for wear and tear and either determined to be refurbished, replaced with like materials, or found safe and suitable to go back on the engine. The list of parts is extensive, but here are the highlights from the last few months.

working on the fire pan

New steel  plate installed in the firepan.

firepan with text

This image shows the old repairs (stabilizing the firepan with old rail) re-worked onto the new steel fabric under the pan.

The firepan and damper box had to have extensive work done on them. The bottom of the firepan was replaced with steel plate. The old firepan had been reinforced with 40 lb. rail in two places. The ends of the old rail had been forged smaller to fit flush with the firepan and then riveted on. This kind of repair clearly demonstrates the thriftiness and ingenuity of a lean short line railroad. The lead restoration worker was unable to determine whether or not this firepan was the original one from 1922. An entirely new damper box was constructed with exception of the riveted joints. The sides of the box were replaced with plate.  The damper box is now made up of both old and new fabric.

old damper box cropped

One of the more handsome shots of the old damper box

new damper box construction

Scott Botfield applying new sides while saving the old riveted frame.

Moving along to the front end, all the bits in the smoke box were reinstalled. The superheater elements, that had been tested previously for leaks went in and were tightened with a careful touch to avoid breaking the header. The header is a complex iron casting in the front end that receives saturated steam from the throttle, distributes it to the superheater elements, collects the superheated steam and delivers it to the piston valves through the distribution pipes.

superheaters going in

Scott installing the superheater elements

superheaters in

All done!

When the original nozzle stand was tightened back into place, one of the mounting flanges broke off while being tightened down. Inspection at the break revealed that the metal was extremely thinned from 94 years of being exposed to the corrosive environment of the smoke box. Miraculously, the new old stock replacement part was found outdoors alongside the warehouse. It was in pristine, unused, unapplied condition. The “new” nozzle was identical to the old one. Finding this part was a huge time saver, for had we not found it, we would have had to make a pattern and send off to the foundry for casting. Volunteer Robert Williams came in and machined the new holes for the studs and fly cut the base, as the “new” nozzle stand was a rough casting.


On the left is the old nozzle stand. Note the thinness at the base compared to the “new”  nozzle stand on the right. 

machining new nozzle

Here is the shop set up for machining the nozzle stand. 

After the nozzle stand was tightened down,  the petticoat and smoke box netting were installed. The smoke box ring and door were freshened up and placed back on making the front end look like its old familiar self.

smokebox front

Freshening up the smoke box ring

The bell was polished by spinning on a lathe and reinstalled after new pins had been made.

bell before


Polished bell



Here is the refreshed bell on its way to No.28. 

The sand dome went on.dome going back on


At the cab, the floor and cab braces were patched with new steel, replacing the old, bent and pitted plate that was there before.


patch Engineer's side floor

Where old meets new on the Engineer’s side floor



Lagging and mud

The lagging bricks are in the back and on the steam dome, the foreground shows the “mud”. 

The lubricator lines were reinstalled and then the lagging was applied. The lubricator lines go in at this time because they travel all along the boiler from the backhead. They are hidden under the jacket.

The lagging (insulation that covers the boiler) is composed of calcium silicate blocks. Until the early 1980s it contained asbestos. All of the material used today is asbestos free.  The blocks are held in place along the boiler barrel with wire, and then given a rough top coat of “mud”. The mud is calcium based cement that is plastered into the crevices between the lagging blocks. This insulation helps to retain the heat in the boiler. It also evens out the surface of the boiler so that the sheet metal jacket has continuous support beneath it which keeps it smooth and good looking.

Now we are working inside the firebox adding new refractory brick after reinstalling the old burner.  The burner is a Von Boden, made in San Francisco.

bricks going in

New refractory brick commencing at the damper box, eventually it will cover the bottom and sides of the firebox, leaving a space for the Von Boden burner shown at the  center.

Meanwhile Eric is putting the finishing touches on the tender and also painting the plumbing lines and accessories.

tender paint prep

Prep for the tender was extensive. Assistant Eric Dowty filled pits and dings, and then primed. 

fresh tender and many bits

In the back ground, the final paint on the tender, and the foreground showing all the bits that will be painted soon. 

The steam fountain comes next. It is the main manifold located at the top of the boiler in the cab that distributes steam to all of the accessories.  It comprised of the main steam shut off (turret valve) and other associated valves that control the flow of steam to all of the accessories such as the injectors, air compressor, fireman’s manifold, etc.  Look for details on our next blog entry.

Replacing the flues and getting the boiler water tight.

Back in the early 20th Century, when labor was inexpensive the boiler flues were assessed and if found to be sound, they were cut out, cleaned of scale and then reused. This was because material was expensive. Today, it’s the other way around, materials are relatively inexpensive compared to the cost of labor it would take to clean and repair 148 flues.

Now that all the old tubes are out of Engine 28’s boiler and the crown sheet has been repaired, and stay bolts replaced, we are completing the tube job and getting closer to the hydrostatic testing.

Photo of tubes with letter key Fig 1

This image is a close up of the tube sheet, also called the flue sheet. You can see that the tube sheet has been cleaned and ground off (C), this was done to clean up any chipping or unsavory remnants left behind from the removal of the old flues. Removing the old flues requires the use of force in hand with some sensitivity to the surface of the flue sheet. However, at times even the most seasoned boiler worker can chip the flue sheet.

The copper ferrules ( F) are gently tapped into the flue holes with a hammer. The ferrules are expanded into place to ensure that they do not move when the tube is applied.  They act as a seal between the tube sheet and the new tube. Next, the tubes are inserted into the flue holes (D) leaving  a small protrusion.   The standard measure of protrusion of the new tube is ¼”. Then they too, are expanded and rolled. The result is a tight fitting tube with a visible indentation on the interior (A ) and a slight flare at the end of the tube. The extra ¼” of tube allows for a good bead (B) that seals the flue to the flue sheet and makes the boiler water tight. After the beading of the tubes, another light roll is given to each new tube because the beading is an aggressive action.

Beading is an art. It involves using a pneumatic hammer or riveter and a specialized tip. In the image above (E) shows a bead that is rough, and (B) shows a bead that is more controlled and refined. It takes a bit of practice to get all the beads looking smooth, but regardless of the appearance, the work will hold.


This image shows the business end of the tube roller/expander. The old rusty shaft next to it is one of the older pieces of a previous roller/expander from the earlier days of boiler work in the roundhouse.

For this project we used this modern electric motor to roll and expand the tubes ( left), but back in the day a pneumatic model would be used ( right)..

Fig 5 drawing from REB

This diagram is from The Railway Educational Bureau Instructional Papers of 1927. It shows a beaded flue end from the side and the front views.

Phil beading, Fig 6

Here you can see Phil Hard beading one of the flues. The pneumatic hammer weighs over 20 pounds, so you can imagine the amount of strength required to do beading all day.


After all the beading is done, each flue then gets another straight roll to ensure the tube is tight in the flue sheet. Beading is intrusive work and it can cause the flues to loosen. The final roll remedies this.

expander rollers Fig 7

These are the tips that are used with the electric motor for the final, straight roll.


After all the beading and rolling, it is time to fill up the boiler and check for any leaks. With the boiler full of cold water at local pressure we begin to assess and address leaks. Once these are addressed it will be time for a true Hydrostatic Test, adding pressure and heat to the 93 year old boiler of Sierra Engine No. 28.


Installation Of Staybolts


Now that the firebox sheets have been replaced, the primary focus is now on the installation of the staybolts. Approximately 300 staybolts were cut out in the areas where the new firebox sheets were applied.


Assortment of old staybolts that were removed.

The firebox sheets are supported by many stay bolts. The boiler shell (wrapper sheet) around the firebox has a water space between the inner and outer sheets.  The staybolts function is to hold the boiler shell and the firebox firmly together.

flex stay-bolt

Diagram of a Flexible Stay-bolt showing the wrapper sheet (left) and the firebox sheet.


Staybolt layout



The original stay-bolts were 3/4” diameter according to the original build sheet. The new stay-bolts are 1” in diameter. They are increased in size due to repeated renewal of the threads during the tapping process. Re-threading the staybolt holes ensures a snug fit with the new staybolts.  The holes are stepped up in 1/16″ increments.


New staybolts  awaiting installation.

A staybolt tap is used to clean up the threads prior to installation of the stay bolts. An air motor is used to turn the stay bolt tap to cut threads in the wrapper and firebox sheets. The staybolt is then threaded into the sheets and the ends peened over with an air hammer.


Tools of the trade.  Three reamers and a staybolt tap.



Running a reamer through a mud ring rivet hole.



Bucking Bar

While the staybolt is being driven with a pneumatic hammer it is simultaneously being braced. To prevent damaging the staybolt’s threads, the opposite end must be supported. A bucking bar is placed on the end of the staybolt to back it up.


Peened staybolt.



Annual Maintenance on the Sierra No. 3

Every year, in accordance with the Federal Railroad Administration Regulations (FRA), Railtown 1897 State Historic Park conducts an annual inspection on all operating steam engines. Locomotives that are not operated often enough to accrue either 31 or 92 service days in a 368 day period will have those inspections conducted, at a minimum, of once every 368 calendar days. This annual inspection is a preventative maintenance approach to keeping this famous “Movie Star” locomotive in prime running condition. All moving components of the locomotive are investigated and gone over with a “fine tooth comb”.  Active engineers on the engine give their input on running condition and what may need to be examined. Overall the No. 3 was in exceptional shape and only needed a few minor modifications during this year’s winter maintenance.


Smoke Box cleaned.

One of the dirtiest tasks maintaining a locomotive is cleaning the smoke box. The most efficient way to remove ash and soot from the smoke box is to crawl inside the smoke box and manually shovel and brush the debris out. The hard to reach areas can be whisked through the clean-out plug located on the bottom of the smoke box. On a very active locomotive a smoke box must be cleaned every 90 days. With the minimal use of the Sierra No. 3, it is only required once a year.


Tender removed from the cab to prepare for maintenance.

Here we see the engine’s cab separated from the tender. The tender was taken outside of the roundhouse to allow working space both for projects on the engine and tender. The tender’s interior was wire brushed to remove scale and debris build up, while the engine was lifted with air-jacks to inspect various maneuvering facets of this locomotive.


Park employee’s Phil Hard and Scott Botfield removing the drawbar from the engine and the tender.

A drawbar is a solid coupling between the engine and it’s load. The drawbar is removed annually and examined for any cracks. After removel, a thorough cleaning must be done.


Park Volunteer Garret Hanford removing grease and debris from the drawbar.

First, grease and other substances must be scraped off. A grinder with a cut brush will remove the rest of the surface debris. Once cleaned down to the bare metal, it is ready for a 3 part dye penetrate examination.


Park volunteer Dave Tadlock applying dye penetrate to the drawbar.

First it is sprayed with a cleaner. Once dry, it is sprayed with a colored dye. If there are any cracks the dye will submerge and be seen after the final step. Next, the colored dye is then wiped off with a rag. The final step is spraying the drawbar with a developer. At this time if there are any cracks they will stand out through the developer. Luckily there were not any cracks discovered.


Journal box staple seen between center spokes of wheel. (Note: Skewed leaf springs)

Examining the geometry of the leaf spring suspension and observations of an arm moving too close to the frame, it was decided that adjustments were in order.  It was determined that the journal box staples needed to be removed, built up, and milled to exactly 11”.


Journal box staple removed.

This journal box staple was removed, measured, and inspected.


Park Employee Scott Botfield adding weld to build up the staple.

After measurements and calculations, weld was affixed to the staple legs to lift it to slightly above 11″.


Affixed weld on staple.

Weld applied to staple legs and waiting to be milled.


Machinist Tony Stroud milling the staple.

Milling or machining, is a process of using rotary cutters to remove excess material. This process will ensure precise sizes and shapes. Here we see the journal box staple being milled to exact specifications.


Journal box staple in process of milling.

Milling the staple to precisely 11”.


Journal box staple after milling process.


Park Employee Scott Botfield using a cutting torch to cut off excess slag.

A cutting torch is used to remove excess material from the legs of the staple.


Scott Botfield using a chipping hammer to remove slag from the staple.

A chipping hammer is used to remove remaining slag (waste material) from the staple. It was then planed with a grinder.


Journal box staple and leaf suspension reassembled.


Scott Botfield using a cutting torch to remove a section of the brake bar.

30” of the brake bar was removed and replaced due to apparent defects. The section was removed by a cutting torch and a new section was welded into place.


Park Volunteer Eric Nielsen doing the “Dirty Work” of cleaning the pit.

While the No. 3 was removed from the roundhouse for inspection, park volunteers were able to clean out the pit and surrounding shop area. A clean work space will enable future maintenance to be performed safely and more efficiently.

The Sierra No. 3 was inspected, fine tuned, and is awaiting park visitors for the upcoming running season.



Railtown’s Motor Car Collection

Behind the scenes at any railroad is the mighty track car. A track car or speeder (also referred to as railway motor car, putt-putt, track-maintenance car, crew car, jigger, trolley, quad, trike, or inspection car, and also known as a draisine (although may be unpowered), is a motorized maintenance vehicle used on railroads around the world by work crews, track inspectors and emergency response crews to move quickly to and from work sites. The track car is slow in comparison to a train or automobile, it is called speeder because it is faster than a hand car or human-powered vehicle. Most cars have a top speed of about 35 MPH. Track cars are small in stature however these maintenance of way vehicles perform any number of tasks.  On modern railroads, this unique type of vehicle was replaced by ‘Hi-Rail’ (or HyRail) vehicles.  Hi-Rails are modern trucks specially fitted with flanged wheels.  The rail wheels can be raised and lowered as needed and they are legal for use on both the highway and rail.

At Railtown 1897 State Historic Park, track cars are most often seen as “fire patrol”, ferrying a crew of dedicated volunteers that keep a lookout for fires started by errant sparks from our steam engines and to promptly extinguish the flames.

Not all of the speeders in use today are historic to the site. We catalog here, a visual sampling of the speeders or motor cars at Railtown 1897 State Historic Park. Some of the more restored speeders are the ones we use in daily operations while the older and more “crusty” looking ones are kept intact as collections pieces because of their documented relevance to the Sierra Railway during the earlier years of operations, before the diesel era.  In the preservation world, they are highly valued for their original, unrestored condition in their original context.  Under the Secretary of Interior’s Standards for Preservation, this is known as preservation integrity, and we work hard educate visitors to appreciate them in this state.  Anyone can apply a fresh paint job, but it is rare to find original equipment, in original context, in un-restored condition.

Meet the Track Cars


MW 80 “Great White”

MW 80 is known among the engine crew as the “Great White”.  A Fairmont A-8 motorcar, it came to Railtown from the Sacramento Southern Railroad at the California State Railroad Museum. We use this car often during the operating season, and since it holds 8 people it is usually our offering for special events that include speeder rides.


SRy #102

Tucked away in the track auto house or “Speeder Shed” is speeder #102. It has been here since the early years. It is a Fairmont A5-A series car, this dates to the early 1930’s. These cars were called Large Extra Gang Cars and could carry up to 11 workers. No longer operable, its engine is a Continental Motor Company Red Seal, 4 cylinder engine. With parts missing, and a frozen engine, it may sit for quite some time as is.

speeder 104, small cropped

Sry #104

Sry #104 is one of the older Sierra motor cars. It is a Fairmont A5 series B-4 manufactured around 1937. The car operated with a 4 cylinder Waukesha engine, and has a capacity of 9 men. This car was once abandoned at Chinese Camp, and came to Railtown 1897 State Historic Park in the early 1990’s.

SRy 106 in machine shop of the roundhouse.

SRy #106 in the machine shop of the roundhouse.

SRy #106 is a sister car to the 104, it is of the same make and manufactured in 1937. It operates today, but is reserved for very special occasions. It has a canvas top. It was acquired from the Sierra Northern Railroad in Oakdale in the early 1990’s and brought back to Railtown. Both the 104 and 106 ran on a Waukesha 4 cylinder engine. Today, both are kept under cover.

SRy #108 May 1978, Jamestown, CA

SRy #108 May 1978, Jamestown, CA

SRy 108

SRy #108-current condition.

SRY #108 is a newer Sierra addition. It was painted SRR 108 back in 1978. This Fairmont  A-5 was part of the original facility acquisition by California Department of Parks and Recreation in 1982. It was probably manufactured in the mid 1950’s. Though it is historic to the site, its age puts it right on the cusp of the advent of the diesel era and Railtown’s period of significance.  Today it is fully operable and is carfully cared for by our dedicated volunteers.

june 2012 097

SRy #110 with park volunteers.

SRy #110 is a Fairmont M19-AA two man light inspection car. It also is a later Sierra acquisition from the Western Pacific. It was manufactured in 1955 and is operable. This model is configured with the aluminum cab and painted “federal yellow”.

SRy 114

SRy #114

SRY #114 is also a newer addition to the Railtown roster. This motor car came from the Western Pacific originally.  It has had extensive rehabilitation work done on it in the past few years, including a new engine, paint job, and most recently a new tool box. 114 is currently running as our primary “fire patrol” speeder. This type of motor car is a Fairmont A-5.

SR MOTOR B full body shot

Sheffield #33

This is by far the oldest and most mysterious motor car at Railtown. It is a  Sheffield No. 33 model. It has a 2 stroke, 3 cylinder engine with a direct drive. This means you pushed the car to start and away you go. No idle, it runs when on. Records show that there were six of these running along the Sierra lines in 1922. This one is probably a remnant from this original fleet. It is stenciled “S.R. Motor B.” in white with dark red body.

W.P. S-2

Western Pacific S-2

Out on “speeder hill” at Railtown, you can find a number of speeder bodies and parts that are sometimes used for surplus. There are two relatively intact speeders on the grounds that were acquired by the Sierra from Western Pacific. Manufactured in about 1960, one of these cars (above) has a belt drive, and the other (below) has a transmission. We do not have record of Sierra numbering for these cars or if they ever ran on the Sierra line.

W.P. S-2 T

Western Pacific S-2T

Olivia dehaviland

Actress Olivia de-Haviland driving the #8 during the filming of “Dodge City” 1939.


SRy #8 Model T

One of our crown jewels found in the historic belt driven machine shop is SRy #8. This Ford model T is mounted on a Fairbanks-Morse frame and dates from around 1922. Though technically a track auto, this two-seat rolling stock was most likely used for light track inspection, or as a paymaster’s car. Today, the car still operates for special occasions, but does not go far from the Roundhouse.


#19 “Hetch Hetchy”, circa 1920 at the San Francisco Muni shops where it was built.

june 2012 128

#19 “Hetch Hetchy” with park volunteers.

The #19 “Hetch Hetchy” is an upscale track car. Its frame and motor were built in 1919 by the White Motor Company. The passenger body is by Thompson-Graf-Edler of San Francisco and interior appointments by Meister & Sons of Sacramento. The front rail trucks, wheels, brakes and self-contained turntable were added by the San Francisco Municipal Railway shop. The first “track bus” No. 19 could carry thirteen passengers, but was originally furnished as an ambulance car during Mountain Division construction and was used on the Hetch Hetchy dam project. Faster than most “speeders”, it originally could travel up to 5o MPH on level track, running in overdrive. This vehicle was refurbished to its original configuration and operating condition at Railtown 1897 State Historical Park in 1998-1999.

More on this unique track car: Hetch Hetchy Railcar #19


Historically, the track autos were used for track inspection, to transport VIPs to work sites, as the paymaster’s car,  or as ambulances for injured workers. The Sierra Railroad rented them out for private use in the early 1900’s.


Newspaper article taken from the Pott’s family scrapbook, 1907.

It is interesting to note how expensive it was to rent the track auto (with chauffeur) for a day, $15.00. That would be about $300.00 in today’s currency.

Visit Railtown 1897 State Historical Park to see the motor car collection in person. During special events you will have a rare opportunity to take a ride on the house tracks in one these unique cars that were once vital to the railroad.

Fabrication and Installation of Boiler Patches


No. 28

No. 28

The No. 28 project is moving right along. Recent focus has been on replacing thinned sections of the firebox. The firebox was assessed after a thorough descaling of  water deposits. Through ultra sonic inspection the crown sheet, knuckle, and area under the firebox door all showed some signs of thinning. The original crown sheet and knuckle were removed and were sent out to have the pieces replicated. The fabricated crown sheet was formed at Benicia Fabrication & Machine, Inc. in Benecia, CA., and the knuckle was formed by Chelatchie Boiler Works, Inc. in Camas, WA..

Original crown sheet being removed.

Norm Comer cutting out original crown sheet.

Portions of the boiler that needed to be replaced were removed in sections by a cutting torch. These pieces were lowered with a electric chain fall and sent out to be duplicated.

Crown sheet removed from     the interior of the boiler.

Crown sheet removed from the interior of the boiler.

Once the crown sheet was removed, the exposed interior of the wrapper sheet was needle scaled to remove accumulated water deposits. After a detailed cleaning the wrapper was inspected for defects. No issues were detected.


Crown sheet marked for stay bolt holes.

After the crown sheet was formed and returned it was then laid out and measured. The sheet was marked in a grid format. 130 holes were drilled on each half of the crown sheet. These holes will later be tapped and threaded to receive stay bolts. The stay bolts will connect through the wrapper to the firebox sheets.


Tony Stroud and Phil Hard.

Stay bolt pilot holes were drilled out at 7/8” and later will be opened up by aligned reaming to .920. They will then be tapped with a 1 inch-12 continuous thread through the firebox and wrapper.

Original and fabricated knuckle peices.

Original and fabricated knuckle peices.


Scott Botfield beveling the knuckle prior to installation.

Upon arrival, the slightly larger fabricated patches were rough cut to size by a cutting torch. The pieces were then ground down until they fit the side sheets. The edges were beveled down to a V which is needed for the welding procedure.

Engine side of crown sheet installed.

Engine side of crown sheet half installed.


336 (2)

New crown sheet halves tacked into place.


Greg Nelson welding inside the firebox.

Greg Nelson welding inside the firebox. Photo by Dan Ryan.


Greg Nelson welding the seem between the firebox knuckle and crown sheet.

Greg Nelson welding the seam between the firebox knuckle and crown sheet. Photo by Dan Ryan.

New crown sheet and knuckle welded into place.

New crown sheet and knuckle welded into place.


Now that the firebox is patched up a substantial amount of work is on the brink. Next step is to thread the stay bolt holes, then installing the stay bolts.

Previous Sierra No. 28 Update: Hydrostatic Testing of Superheater Tubes

Next Step: Tapping and Installing Stay Bolts.