4-8-2 - 1500 Class Series - Locomotive Scullin Disc Driver Centers Verses Spoke Driver Centers

I have looked at the 4-8-2 SLSF 1522 many times and thought the disc type main driver on the # 2 axle looked out of place next to the spoked drivers on axles # 1, # 3 and # 4.

Then I just saw an old picture on this site with them all spoked.

Does anyone know when this switch out took place and possibly why?

Thanks,

Jerome

 

The Scullin disc-centers, provided a strong, well-balanced design for the modern locomotive.

Please see the following link.

http://www.frisco.org/vb/showthread.php?6518-Scullin-Driver-Patent-Jan-25-1936&p=49055#post49055

Edit 4/8/2024: Trying to repair the broken link above. As an alternative, please see the following link.

https://www.steamlocomotive.com/types/drivers/

Added an alternative link discussing Scullin disc driver centers.
MKD

 

Thanks.

After looking around here and seeing Karl's nice posting on the Scullin disc driver centers I guess it was not all that uncommon of an upgrade.

I also wanted to ask if there was a source for drawings of the 4-8-2 SLSF 1522 or other late 1500 series that had Walschearts valve gear?

I am contemplating building a large scale locomotive and trying to assess if the SLSF 1522 would be a good choice.

I figured living in St. Louis and being able to visit the prototype would be beneficial.

Also having had the thrill to take an excursion on it sure makes it a sentimental choice as well.

Thanks,

Jerome