Ogden Union Station

WRC made a trip to Ogden in mid-April to work on two different projects. The first project involved the repair of a Davenport 44-ton diesel locomotive that will be useful to the folks at Ogden if it is up and running. This involved some collision repair and a mechanical evaluation. Read the story and see pictures here…

Nevada Northern Railway

The second part of the trip involved two passenger cars which were interchanged by rail from Ohio to Ogden, UT. The Ogden Union Station was gracious to keep the cars on their tracks until arrangements could be made with crane and trucking companies to complete the journey to their new home in Ely, NV.

WRC was on site to oversee the disassembly and loading of these cars on to trucks. The pictures and story can be found here…

Union Pacific Steam

WRC continues to assist the Union Pacific Steam Crew in completing repairs to No. 3985. A short update and pictures of the firebox work completed can be found here…

Monte Holm Equipment

Check out the Classifieds for information regarding the Monte Holm Equipment.

From the photos of 3985's firebox, it appears that the side sheet patches are in areas that had circulators. Is that indeed the case, and when and why were they removed?

Howard P.

Hello Howard,
Actually, the major patches are below the circulators. However, after long and careful review, the UP Shop staff decided that removing all five circulators would be in their best interest over the long run.
The consequences of this decision is that there will be roughly 300 less square feet of heating surface, which is felt will not be detrimental to the current requirements of the engine. We examined the 3977 at North Platte and found it had all of its circulators removed by the UP in the steam days, we also found in the drawing files instructions on completeing this work.
Hope this helps.
Respectfully,
Dave Griner
Chief Mechanical Officer
Wasatch Railroad Contractors

Dave,

It is my understanding that the reason for installing the circulators in the first place was not to increase the surface area but to improve the circulation of cold water on crownsheet particularly in back of the firebox. While it may have been determined that the reduced surface area, may not significantly decrease engine performance, have you analyzed the impact it will have on water circulation in the area of the firebox?

Was there onlly a single Challenger with no circulators? If the UP only operated a single Challenger with no circulators, it suggests to me that this may have been more of a failled expeiment than a viable improvement.

What was your rationale in recommending this step to UP?

Since this string came back up from the back pages I have a question as well. On your home page photos of the 3985 work it appears that there are patches on the outside side sheets where the circulator washouts were. The patches are stayed with a circular pattern of flexible staybolts. The spacing does not match the spacing of the solid bolts around the patches. Why use flexible bolts right in the middle of a field of solid bolts? This isn't even on the edge near the flexies at the crown but way down in the center of the sheet. Perhaps I have not identified what this really is but the flexies are where they are.

What was the thinking/engineering behind this? I would have thought that the patch would simply be inserted much like your other patches and then stayed with solid bolts matching the pattern/spacing.

I also wondered about the circulators in that the heating area was not the reason that they were in there in the first place. Are they being removed because they were a maintenance headache or that they were in need of replacement so then they were simply taken out. Not so simple of a job though.

Hello Adam & Barry,
Thank you for your interest in the 3985 project.
You are correct in noting that the circulators promote better circulation, however, we researched the ramifications of their removal and concluded that it would not impact the current and expected requirements of the engine. It should be noted here that 3977, preserved in North Platte, was inspected and found to have had the circulators removed by the UP in the steam days and was in operation under those conditions.
The UP staff considered all the options and decided that their removal would be conducive to future maintenance. We supported the decision making process through experience and extensive research, concurring with the final result.
We are unable to determine just how many engines were subject to this revision, however, drawing # 146CA31251,titled “Removal of Security Circulators-Firebox Alteration”, dated 8-18-44, notes being applicable to “class 4664-3,4, engines 3950-3999”, with revision A being applicable to class 4664-5, engines 3930-3945”. We have a thought that this change was based on possible excessive repair due to a myriad of reasons, one of which could be bulging as a result of localized overheating, having found evidence of this on 3985. Again no solid reason could be determined.
It was decided to leave the bulges on the wrapper sheets, only patching the washout plug holes for appearances and reducing the impact to the project time line. The use of flexible bolts was also a matter of convenience. Staybolt pitches were established to conform to the FRA rules.
Again, thank you for your interest.
Respectfully,
Dave Griner
Wasatch Railroad Contractors

Then I have another question. If the firebox sheet staybolt pitch is 4"x4"=16 insq but it's attached to the wrapper where the pitch is 4"x9"= 36 insq, what is the load on the staybolt (200psi x 16 OR 200psi x 36????)

and please show your math.

Hello Mr. Mizer,
Again thank you for your continuing interest in locomotive work.

Typically when staying two plates of the same thickness, the pitch will be the same, hence the stress on the bolt will have only one number. However, there are numerous instances where the dimensions on one side are not equal on the other. When this happens the applicable pitch is, to quote the ASME Code, “ p=maximum pitch measured between straight lines passing through the centers of the staybolts in the different rows, which lines may be horizontal and vertical, or radial and circumferential” 1992 Edition.

So, in a situation where there are two different pitches for flat plates of the same thickness the largest pitch governs the calculated load on the bolt.

The applicable formulae are t=p times the square root of P/SC and
P=t squared times SC/ p squared.
Where t=plate thickness, P= Maximum Allowable Working Pressure,
S= Maximum Allowable Stress, p=pitch as defined above, C=constant for attachment method.
There is more to it than that, but this is the basic work.

When we get into a curved wrapper the whole problem takes a different turn and becomes a bit more challenging due to the pressure retaining capabilities of a curved surface---we’ll leave sleeping dogs lie!

The real point of interest is determining the stress on a given bolt, which is determined by dividing the load by the functioning cross sectional area of the bolt, (L/a). The FRA rules are explicit on this number being not more than 7,500 psi. for staybolts and 9,000psi for braces. Many times in doing Form 4 work these limits bring about interesting problems.

The Engineering Standards Committee has published a Compendium of these and other calculations, if you are interested they can be acquired for $25.00. Let me know if you would like to acquire a copy.
Thank you again for the opportunity to discuss locomotive boiler work.
Respectfully,
Dave Griner
Wasatch Railroad Contractors