Flexible Staybolt Design and a Boiler Factory Tour

Photos and text by Pete Deets

Staybolt Update

No, this is not a fleet of UFO’s lined up at SPEC Machine. These are the caps for the latest batch of flexible staybolts being made for the 1385.

 

The caps and sleeves shown (above) and the staybolt itself is completed when a ball end (below left) is threaded onto the bolt and the bolt is placed into the sleeve (below right).

Below is a comparison of the two types.

You may wonder why we need 2 types of flexi’s. That is because we have to allow for support of curved as well as flat surfaces. This illustration from the 1938 Flannery Staybolt Catalog shows how the first batch of staybolts will be applied. This is the UW style and is designed to be used where the staybolt will be going through the supported sheet at close to a right angle and the inside and outside sheets are very close to parallel. The flexible staybolts on the throat sheet at the front corners of the firebox will utilize the UW style.

The latest batch is the WR style which is designed to be applied where the inside and outside sheets curve at different rates and do not run parallel. This is the situation near the top of the wrapper sheet and firebox. Because the top of the firebox (the crownsheet) is rolled in a tighter radius than the wrapper sheet and the rigid end of the staybolt needs to be square to the sheet it is attached to the flexible end goes through its’ sheet at some angle.

All these parts are coming together and will be forming a boiler very soon.

A Look Inside the Continental Fabricators Factory

I took a quick trip with Steve & Tyler Roudebush of SPEC Machine to deliver a palette of parts to Continental Fabricating in St. Louis as well as inspect the progress on the new boiler for 1385. More photos and details about the boiler will be posted later but I wanted to share a few shots of Continental’s shop. I hope this will give folks a feel for the size of operation building our vessel.

 

1385 Project in BIC Magazine

Continental Fabricators was recently highlighted in Business & Industry Connection magazine. In discussing current projects at Continental, boiler fabrication for US Sugar #148 and Mid-Continent’s own C&NW #1385 were highlighted as the type of specialty projects Continental is capable of tackling.

You can check out the digital edition of the magazine, which includes a photo of 1385’s boiler.

BIC Magazine’s circulation includes industry managers and executives  in the  refining/petrochemical, drilling, pipeline, marine, terminal, pulp and paper, power generation and heavy construction industries.

Preparing for Backhead Stay Installation

During the last week of January Continental Fabricators began installation of the 1385’s backhead diagonal braces. The backhead is the end of the boiler located within the cab and is a large, flat plate or sheet of steel that has been flanged and then welded to the wrapper sheet.  Flanging is the process of very carefully curling the edges of a sheet to meet the next piece it will be mated to.  The flanging process has been covered in previous update posts.

Much of the boiler is round, a naturally strong shape.  With areas that are flat or nearly flat the forces of nature (including steam pressure) are constantly trying to force them round and thus they require support or “staying”. Staybolts, or “stays” and braces are thus used to reinforce the area and prevent the backhead as well as the other flat areas from bowing outward when the boiler is under pressure.

firebox diagram

While installing these braces, crews at Continental Fabricators flipped the wrapper sheet/backhead assembly upside-down to facilitate easier working conditions. The first photo below shows the assembly as of the last week of January 2019 as the braces are being fitted and tack welded in place.  The tack welds are just enough to hold the braces in place so this assembly can be righted and lowered onto the firebox/mud ring assembly to check for proper clearance between the braces and the firebox.  Once Continental is satisfied with the fit-up between the pieces the wrapper assembly will once again be pulled off the firebox, inverted and the braces will receive the final welds.

upside-down wrapper sheet and backhead

Much of the backhead will be supported via staybolts connected between it and the firebox door sheet. The pictured diagonal braces are used to support the part of the backhead that does not line up with the door sheet and is instead connected to the wrapper sheet for support. This picture was taken during the last week of Jan. 2019. Photo courtesy Continental Fabricators.

A few days later during this the first full week of February, Continental’s crews had flipped the backhead/wrapper sheet assembly right-side-up again and placed it over top the firebox/mud ring assembly. The purpose of doing this is to test fit for any contact between the backhead braces and the firebox crown sheet before final welding of the braces and before the wrapper sheet/backhead assembly is welded to the firebox/mud ring assembly.  Once the two assemblies become one the installation of the staybolts can begin.

1385’s Boiler Assembly Continues

The following is an update on C&NW #1385’s new boiler progress comes courtesy of Continental Fabricators. Continental is the company creating the new boiler for the 1385.

The wrapper sheet has been removed and welding is complete except for the wash out plugs.

The wrapper sheet was fit to ensure all of the firebox stay locations lined up correctly then removed so that we could drill the firebox, as you can see the doorsheet is all that needs to be drilled.  After this is complete the wrapper will be fit and welded for the last time and the entire boiler assembly will be welded together, followed by stay installation.

This photo shows the test fit of 1385’s wrapper sheet and progress with drilling. Photo courtesy Continental Fabricators

When the boiler is completed it will be delivered to Wisconsin where the locomotive will be assembled at the shop of SPEC Machine.

Tender Moved to Live Track

On October 25, 2018 a team of cranes were at Mid-Continent. The cranes were primarily there to install locomotive #1256’s new wheels, but the 1385 Task Force took advantage of the presence of the cranes to move Chicago & North Western #1385’s tender to live track.

For the past five years, ever since arriving from the fabrication shop, the 1385’s tender has resided on an isolated display track along the passenger platform. The covered platform display area provided a cozy home for the tender where the public could learn more about the restoration while the locomotive itself was overhauled off-site.

All photos courtesy Richard Colby.

With the boiler nearing completion and reassembly of the locomotive’s major components set to begin in the coming months, it was a good time to also prepare the tender for the locomotive’s eventual return.

Volunteers and members of the crane crew set about removing the tender from the shelter. First it was chained to the museum’s Lull forklift and towed out into the open where the crane could get at the tender to disassemble it. The trucks were then moved to the museum mainline and the tender reassembled. Once done, Mid-Continent’s yard switch engine, MCRY #4, coupled on and took the tender to the museum’s Engine House.

The tender, mostly while mostly complete, still has some finishing touches needed including items such as the air brake system, steam heat pipes, and electrical systems (for reversing headlight, class lights, safety lights, etc.) The wheels will also need to be jacked and the roller bearings inspected for possible damage from the August floodwaters.