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Santa Fe #2926 Runs Under Steam For The First Time Since 1954

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Posted by kgbw49 on Monday, August 16, 2021 4:59 PM

We will take the "W"!

Meanwhile, a question popped in to my head regarding the rebuilding of the 73-inch-drivered 3751 class in to 80-inch drivered locomotives.

Might they have needed a small insert to the boiler and perhaps a new frame or extended frame to fit four 80-inch drivers where 73-inch drivers used to be?

I know the Missouri Pacific needed to do an insert when they converted their 63-inch-drivered Berkshires to 75-inch-delivered Northerns.

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Posted by Overmod on Monday, August 16, 2021 5:49 PM

kgbw49
Might they have needed a small insert to the boiler and perhaps a new frame or extended frame to fit four 80-inch drivers where 73-inch drivers used to be?

The rebuild in '41 involved a new cast engine bed with roller bearings.  To my knowledge the boiler was not enlarged.

3751 was the last to be rebuilt for an interesting reason.  She was modified with a Batz high-speed lead truck (with larger wheels), improvements to valve motion, etc. as protect power for the Super Chief in 1936.  Consequently by the time of the 'second' rebuild she got the benefit of all the revealed wisdom from both the first and second 'batches'.

I believe there are contemporary accounts of the detail rebuilding in the trade press, as there is for the late-Forties second rebuilding of the awesome C&NW H locomotives, but I cannot find it on a phone.  Here is a modeler's reference which pointedly says nothing about boiler mods:

http://sfrhms.org/files/ThompsonJohn/4-8-4%20Clinic/4-8-4%20Clinic.pdf

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Posted by M636C on Monday, August 16, 2021 9:30 PM

Overmod

 

 
kgbw49
Might they have needed a small insert to the boiler and perhaps a new frame or extended frame to fit four 80-inch drivers where 73-inch drivers used to be?

 

The rebuild in '41 involved a new cast engine bed with roller bearings.  To my knowledge the boiler was not enlarged.

 

3751 was the last to be rebuilt for an interesting reason.  She was modified with a Batz high-speed lead truck (with larger wheels), improvements to valve motion, etc. as protect power for the Super Chief in 1936.  Consequently by the time of the 'second' rebuild she got the benefit of all the revealed wisdom from both the first and second 'batches'.

I believe there are contemporary accounts of the detail rebuilding in the trade press, as there is for the late-Forties second rebuilding of the awesome C&NW H locomotives, but I cannot find it on a phone.  Here is a modeler's reference which pointedly says nothing about boiler mods:

http://sfrhms.org/files/ThompsonJohn/4-8-4%20Clinic/4-8-4%20Clinic.pdf

 

That Thompson paper is a good resource for individual 3751 class locomotives.

While the boiler wasn't lengthened, the smokbox was lengthened. Sadly I can't quote a number of inches, because while the rebuilt locomotive drawing shows a distance from the tubeplate to the centre of the blastpipe, the original locomotive does not quote that figure.

However, on the original locomotive, the access hatch for the superheater header takes up most of the space between the stack and the tubeplate, while on the rebuild, it occupies only about half the space. This can be seen in some photos.

The smokebox on the 3765 was even longer, however...

Peter

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Posted by M636C on Tuesday, August 17, 2021 9:13 PM

Flintlock76

Amazing.  In a way, it reminds me of the change of appearance of the battleships salvaged from Pearl Harbor and repaired and refitted.

They called them "The Pearl Harbor Ghosts."  They got their revenge at Suragao Strait in 1944, but that's another story.

 

The rebuilding of the battleships from Pearl Harbor is an interesting comparison, having occurred only a short time after the rebuilding of the second batch of 3751 class.

A good reference to these is Battlships and Battlecruisers 1905-1970 by Siegfried Breyer. This is illustrated by line drawings to a constant scale and illustrates ships at various stages of their lives, in both side elevation and in plan view. One of the best examples was California, which looked like a WWI battlship before Pearl Harbor but looked more like a contempoary South Dakota class after rebuilding. The replacement of the secondary armament with twin 5"/38 turrets provided a useful anti-aircraft capability on many of the rebuilds, including California.

Peter

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