Trains.com

B&O 2-6-6-2

1249 views
7 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    May 2011
  • 183 posts
B&O 2-6-6-2
Posted by IA and eastern on Sunday, October 23, 2022 5:43 AM

B&O 2-6-6-2 7518 was simpled. What was the size of the cylinders and the TE of this locomotive? Gary

  • Member since
    September 2003
  • 19,413 posts
Posted by Overmod on Monday, October 24, 2022 9:36 AM

7518 was never simpled.  The 1949 rebuild provided new front cylinders with piston valves and slightly larger drivers, probably with larger tires a la PRR J1a.  It had 'epic' counterweight boxes on both front and rear mains, which in itself might make an interesting story.

http://www.northeast.railfan.net/images/bo7518s.jpg

I suspect this was an attempt to cash in on the same tax dodge that produced the extensive rebuilding of Frisco 1351/2; note that it is at roughly the same time that the last C&O locomotives of this wheel arrangement were built.

It appears to me that the rear HP cylinders are smaller, which indicates that the boiler pressure might have been increased as part of the rebuilding.

I'd contact steamlocomotive.com and have them put up principal dimensions and performance estimates for the KK-5 class.  Whatever the advantages (either financial or mechanical) they don't appear to have given enough longevity for the locomotive to be reassigned a 3-digit road number; the sources I've read indicate it was scrapped at around the same time as the various KK-4s, in the early '50s.

  • Member since
    July 2016
  • 2,026 posts
Posted by Backshop on Monday, October 24, 2022 4:58 PM

IA and eastern

B&O 2-6-6-2 7518 was simpled. What was the size of the cylinders and the TE of this locomotive? Gary

 

Like others have asked, please stop with your quizzes.  Classic Trains has a couple of threads on questions.  The problem will be that you have to answer one correctly before you can ask one.

  • Member since
    May 2011
  • 183 posts
Posted by IA and eastern on Tuesday, October 25, 2022 1:06 PM

Thank you for your advice. Gary

  • Member since
    January 2002
  • 4,497 posts
Posted by M636C on Saturday, October 29, 2022 7:50 AM

I'm a bit late to this discussion.

I've had Marsupials chewing my internet cable.

However, I decided to check the KK-5 in my B&O references, Stauffer's B&O Power and Edson's Steam Locomotives of the B&O. Neither of these books list any different dimensions for the KK-5 compared to the KK-4 series. Stauffer indicates that the KK-5 was a rebuild utilising new one piece cast steel beds (obviously, two of them). This would increase the weight substantially. Perhaps a new diagram was not issued in 1949. But neither of these references indicate any weights or dimensions, although they do for most other conversions and rebuilds.

So the KK-5 could be considered the equivalent of the new C&O H-6 locomotives, a version of an early articulated suited for extended service under the conditions of the time. Of course, B&O only rebuilt one KK-4 but C&O ended up with ten new H-6 locomotives.

Comparing photographs of the KK-5 with the KK-4, it is possible that none of the leading dimensions were changed. It appears that the HP cylinders had much larger piston valves, which might give the impression  of smaller HP cylinders. Equally, the coupled wheels don't seem to be substantially changed in size.

The boiler is externally the same, and as rebuild centred on an improved frame, it is quite possible that the boiler wasn't changed.

Peter

  • Member since
    May 2003
  • From: US
  • 23,120 posts
Posted by BaltACD on Saturday, October 29, 2022 11:21 AM

Lawrence Sagle's "Picture History of B&O Motive Power" indicates that KK-4b number 7518 was rebuilt into a KK-5 with solid bed castings including cyliners, thicker tires to increase driver diameter to 58" and increased boiler pressure to 215 pounds from 200 in KK-4 trim.  The locomotive had 85K pound tractive effort vs. 80K pounds for the KK-4's.  As of Jan. 1, 1952 there were on KK-2, two KK-4b, one KK-4c and one KK-5 in service - all with uncertain futures.

Never too old to have a happy childhood!

              

  • Member since
    January 2015
  • 2,317 posts
Posted by kgbw49 on Saturday, October 29, 2022 5:37 PM

I have to throw in the comment that it looks like they have given it similar treatment to the 4-8-2 Class T conversions:

https://www.railarchive.net/randomsteam/bo721.htm

http://www.northeast.railfan.net/images/bo7518s.jpg

 

  • Member since
    January 2002
  • 4,497 posts
Posted by M636C on Saturday, October 29, 2022 7:04 PM

BaltACD

Lawrence Sagle's "Picture History of B&O Motive Power" indicates that KK-4b number 7518 was rebuilt into a KK-5 with solid bed castings including cylinders, thicker tires to increase driver diameter to 58" and increased boiler pressure to 215 pounds from 200 in KK-4 trim.  The locomotive had 85K pound tractive effort vs. 80K pounds for the KK-4's.  As of Jan. 1, 1952 there were on KK-2, two KK-4b, one KK-4c and one KK-5 in service - all with uncertain futures.

 

I think we have provided the OP's answer here...

If the boiler pressure is raised from 200 to 215 lbf/sq.in. and the coupled wheels increased from 57" to 58" and the cylinder dimensions remain the same, the tractive effort becomes 84 517 lbf.

The only detail missing is the new weight with the cast steel beds. I have found a weight in Edson's book, 445 600 lbf. This was listed with the B&O articulated locomotives, while all other details are listed in the Buffalo, Rochester and Pittsburgh section, not surprisingly. This compares with the original weight of only 432 000 lbf for the KK-4b that 7518 was rebuilt from. However, the final KK-4d units, built in 1923, weighed 445 000 lbf.

An increase from 200 lbf/sq.in. to 215 lbf/sq.in. may be possible within the safety limits of the original boiler design, or with relatively minor changes.

Incidentally, 7518 lasted until March 1953. While this was only four years after the rebuild it was a full year longer than the last of the KK-4s, suggesting that the rebuild did lengthen times between workshop attention.

Peter

Join our Community!

Our community is FREE to join. To participate you must either login or register for an account.

Search the Community

Newsletter Sign-Up

By signing up you may also receive occasional reader surveys and special offers from Trains magazine.Please view our privacy policy