3/4-inch scale B&O P7d Cincinnatian

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Re: castings for the B&O P7d Cincinnatian

Post by Andypullen » Wed Jul 28, 2021 12:53 pm

Mike Walsh wrote:
Wed Jul 28, 2021 8:35 am
Andy R wrote:
Tue Jul 27, 2021 5:46 pm
Examining the drawings that I had, the complexity of some parts appeared too great to try and fabricate, so a few castings were obtained from John at Friends Yankee Shop. The Brake Hanger Bracket #4134 in particular was a bit of a puzzle regarding how to hold the casting while machining, and in what order the machining was done. Adding to the consternation is the dimensioning - all relative rather than from an absolute reference. All connecting parts had to be consulted. In addition to supporting the brake hangers, these also support the main equalizers.IMG_4199.JPG
I have elected to not (yet) finish any surface that does not need finishing. Paint will hide everything anyway.

Another casting set obtained is the brake hangers, part #8142. These are paired left and right. And holding them was also a puzzle.IMG_4197.JPG
I may thin the web to the dimensioned 1/16 inch, but at this time it appears unnecessary.
Andy, I might have some of these castings (surplus to my needs). I am not sure if they are 3/4" or 1/2" - inclined to think 1/2", but if they are 3/4" and useful to you, you can have them free of charge if you're interested. Can you send me a PM with a photo of the brake hangers and brackets with a 6" scale next to them and I'll look in my shop?
I might also have some of the parts that you need. PM me with photos also.

Andy Pullen
Clausing 10x24, Sheldon 12" shaper, ProtoTrak AGE-2 control cnc on a BP clone, Reed Prentice 14" x 30", Sanford MG 610 surface grinder, Kalamazoo 610 bandsaw, Hardinge HSL speed lathe, Hardinge HC chucker, Kearney and Trecker #2K plain horizontal mill, Haas TL-1 lathe.

Andy R
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Location: So. Calif.

castings for 3/4-inch scale B&O P7d Cincinnatian

Post by Andy R » Wed Jul 28, 2021 6:16 pm

Mike and Andy,
Thanks for your generous offers!
PM's sent.

Andy R
Posts: 302
Joined: Wed Sep 26, 2007 2:18 pm
Location: So. Calif.

A Visit to Baltimore

Post by Andy R » Thu Jul 29, 2021 10:06 am

I had an opportunity to go to Baltimore, so did not pass up a visit to the B&O Museum. I could have spent an entire day or two there, but spent most of my limited time documenting the 4-2-0 Lafayette. I may someday build a 3/4-inch scale version, but it has been significantly lowered in priority as a project. The surviving P7, the 5300, was stored in the parking lot of the museum, and appeared faded at best. I did examine the offerings in their bookstore, and purchased a copy of:

“Baltimore and Ohio’s Cincinnatian” by Thomas W. Dixon, Jr. published by TLC Publishing. ISBN 0-939487-85-1 (2008).
Wow. What a neat streamlined locomotive! I had recalled reading about it in “Steam’s Finest Hour” edited by David P Morgan, and published by Kalmbach Publishing Company in 1959. I have had a copy of that since I was young.

This is a copy of a B&O publicity photo from 1946.
b&o cincinnatian - Bing images.jpg
The P7 has been modeled in 2.5-inch gauge, in 3.5-inch gauge, in 4.75-inch gauge, and in 7.5 inch gauge, and all that I know about have been of the as-delivered version from Baldwin in 1927. That’s understandable because it was a very nicely proportioned and decorated locomotive. But after reading Tom Dixon’s book, I thought “Why not make mine a little different?” I was sold on modeling the streamlined P7d, four copies of which were reconstructed by the B&O at Mount Claire in 1946. If anybody is aware of another live-steam P7d I will be interested in hearing about it.

Andy R
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Joined: Wed Sep 26, 2007 2:18 pm
Location: So. Calif.

Learning more about the P7d for the Cincinnatian

Post by Andy R » Thu Jul 29, 2021 10:14 am

Additional printed resources were eventually obtained in my effort to find out more about the P7d:

“STEAM LOCOMOTIVES OF THE BALTIMORE AND OHIO, an All-Time Roster” by William D. Edson, self-published in 1992, and

“Baltimore and Ohio Pacific Locomotives – Handsome Passenger Workhorses” by Bob Withers, published by TLC Publishing. ISBN 9780939487615 (2013)

The P7’s were modified extensively during their lifespans. One, the 5304, was streamlined in 1939 for the “Royal Blue” passenger train, and painted blue to match. That became class P7a. I have an American Flyer S-gauge model (#350) of that Dreyfus-styled locomotive. The streamlining on 5304 was later removed. The P7b really didn’t have any externally visible changes, but the P7c, P7d, and P7e modifications included a lot of upgrades including new cast-steel frames, Worthington feedwater heaters, air pumps mounted on the pilot, smokebox insulation, and more. It seems like they were all painted blue. The big difference in the P7d was of course the streamlining, and Timken roller bearings on each axle. The four modified into class P7d were the 5301, 5302, 5303, and 5304. They were assigned to a new passenger train (the Cincinnatian), and remained in service until 1957.

I won't be modeling the cast-steel frame under the locomotive - especially because most of the frame work has already been done. I also evaluated roller bearings and decided that they are not that practical (or needed) in this size. I may put roller bearings on the tender axles - still to be determined.

Andy R
Posts: 302
Joined: Wed Sep 26, 2007 2:18 pm
Location: So. Calif.

Equalizers and such

Post by Andy R » Tue Aug 03, 2021 1:22 pm

I have been working on suspension items. The attached photo shows the cross equalizer and (temporarily) attached spring yokes. These were hacked out of chunks-o-steel. It was time consuming but fun. Mr. Coventry in his original notes wrote: "...otherwise the whole job is straight-forward and only needs care and patience." So true! There are a lot of suspension parts to be made.

Andy R
Posts: 302
Joined: Wed Sep 26, 2007 2:18 pm
Location: So. Calif.

a gaggle of suspension parts

Post by Andy R » Tue Aug 24, 2021 6:54 pm

I have been making suspension parts, some of which have been temporarily attached to check fit-up.
In the photo are parts #1145, 2145, 3145, 6145, 9145, and 9145A.
I'm still working on the two trailing truck hangers #8145.

Andy R
Posts: 302
Joined: Wed Sep 26, 2007 2:18 pm
Location: So. Calif.

Starting fitup of the frame

Post by Andy R » Thu Sep 02, 2021 6:53 pm

The rear cradle fits well, square, and tight. Like the deck plate at the front of the loco, I left the bolts long thinking that I may need to over-drill and use nuts but everything was fitted well.
The same success was enjoyed with the mid frame spreader. The plans show this as solid but the x-bracing is much closer to the existing locomotive. But nobody will notice when the boiler is on.

This was my first mistake so far on the locomotive, which is surprising to me. (The first, not the mistake.) I located, drilled, and in some places tapped, 40 holes in the frame. On one side the 4 bolts for this were drilled and tapped 2-56 per plans, but on the other I drilled #30, because most of the other holes are #30. So there are 5-40 bolts on that side.

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