The final 2015 status report has been posted at http://557.alaskarails.org/…/progress-re…/2015_12/index.html.

Fixed link: http://557.alaskarails.org/restore/progress-reports/2015_12/index.html

Thanks. I posted the main page link in error.

The January status report is posted at http://557.alaskarails.org/restore/prog ... index.html.

The February status report is now available at http://www.557.alaskarails.org/restore/ ... index.html.

March is off to a good start with additional weld passes being done to bring the firebox seams closer to completion. Good progress is being made in fitting sleeves to allow an upgrade of some 400 rigid stays to flexible.

Other work includes the continuing overhaul of the locomotive brake valves and fitting the water and oil valves and piping onto the tender.

Nice work. Your images of this project are always a treat, and an inspiration.

Why are 400 rigid stays being changed to flexis?

Howard P.

These locomotives only had a total of 16 flexies as delivered from BLW, etc. Reliability and low maintenance were goals as we made decisions when contemplating what we wanted our final product to be. When we decided that the firebox had to be replaced it necessitated that all the stays be replaced. After consultation with Robert Franzen, our boiler guru, we decided to convert a number of the rigids to flexies at the same time. This upgrade isn't unprecedented. One of the Ft. Eustis locomotives of the same design had a similar treatment when its boiler was overhauled in the early or mid-1950s.

A point that might be relevant here:

A 'traditional' reason to limit the use of flexible staybolts in 'commodity' locomotive service was the higher cost of the bolts and their maintenance.

That is far less of a consideration for many good restorations that aim to make the locomotive more reliable, or the boiler structure more long-lasting.

Flexible stays cut down on boiler maintenance. When these engines were built during WWII, they didn't expect them to outlast the war.

The 2-8-2's built for the WP&Y are lacking in flexies too.

Howard - There was a long thread on here maybe 8 or nine years ago (I don't have time to find it right now) dealing with flex vs. rigid stays with much good info in it. Point is there is much movement of the firebox sheets relative to the wrapper due to variations in temperature/expansion (as well as plain physical motion of the loco), but mostly due to more rapid changes and higher temps in the firebox sheets. The most pronounced shifting is near the knuckles and can eventually result in warping and cracking of the sheets and bending/breaking staybolts. Flexis still bend, but with one end able to move, the stresses are spread out over more of the length of the bolt (more evenly) so that it's not concentrated right at the sheet entries and torquing the sheets as much.

I also suspect that the difference in price was much higher back then (others have correctly said the War Dept. bought them cheap) when the average git-'er-done RR shop force could have just about any boilermaker apprentice ream/tap/drive/end threaded stays in a hurry, so the savings would have been more significant. Even threaded flexi sleeves require a larger hole properly lined up and I doubt there were single reamer/taps for both diameters due to the huge variety of size and length combinations (Kelly or J. David or someone else could answer better).

As info and at the risk of going off topic, Ed Dickens said there were a number of flexi sleeves (welded type) that didn't line up properly with the holes in 844's firebox sheets and had to be replaced last year, and looks like their cost even for rigids is higher because they're threading the wrappers and using full penetration welds on the firebox end.

That happened when the new sheets were drilled before being fit up during the recent replacement of side sheets. Ended up causing another set of sheets to be made. This time they did the fitting first, then marked and drilled the holes. Amazingly, everything lined up. Who would have thunk it?

Happened to another group in another location with a different loco recently, too. They are also faced with the time and money of replacing new sheets, for the same reason.

The importance was recognized back in 1908...

Really interesting.

They say the way to eat an elephant is one bite at a time. Here are a couple more bites of ARR #557. The combined steam and sand dome casing and the fuel bunker have been cycled through the restoration process and are now back on the shelf and ready to be installed when their times come.

A new status report is posted at http://557.alaskarails.org/restore/prog ... index.html

A new status report is posted at http://557.alaskarails.org/restore/prog ... index.html.