Spring rigging question

[kenrinc]

I'm in the process of examining a number of prototypes for a possible project, in this case Alco and/or Baldwin moguls from the 20's. Looking at a number of drawings, I notice that the center of the very rear leaf spring seems to be attached to the frame at the very back of the last driver. I understand the connection at the furthest point which is similar to how the hangers and keys work on the rest of the spring but need to clarify how the center of the spring is attached. Is there a center bolt that goes through the center of the spring or is the spring just bearing against the frame? I don't see a bolt and it's unclear in most of my drawings since the brake hangers are usually in the way. This drawing is for a USRA 0-8-0 that I found that has a similar arrangement. Appreciate any info.

Ken-

[Glenn Brooks]

Ken, I see no one has replied to your inquiry. You might PM Russ Noe aka NP317. Russ may be familiar with the prototype design you are asking about.

Good luck. Very interesting question about construction detail.

Glenn

[johnpenn74]

Here's a picture of a 1930 Baldwin Decapod in Winder Ga. I am sure this is basically the same treatment as the USRA 0-8-0. If you export the picture and zoom in you can see the right most connection to the spring is a pin through the spring pack like the ones that hook things together when the leaves are on top. Maybe it not sure if it goes through the frame. The practical solution for the model might be simpler like an inverted pin or both through frame. The connection in the middle of the spring is just a frictional seat as is commonly found on the top of saddles allow the leaf to rock and equalize.

The other picture is from another Gainsville Midland engine in Charlotte NC. Again 1930 ish baldwin. I Always liked the 2-8-0 because it had three air pumps.

JP

[NP317]

Those three pictures showed more than I knew about the rear spring attachment method for those locomotives.
All of my prototype knowledge is about locomotives with training axles. Their equalization is set up differently.
~RussN

[Dick_Morris]

From the back end of a CNJ 0-8-0. It gives pretty good detail.

[BClemens]

This is great information in answer to the original question. (with a plan photo too!)

This 8-10-D has the 'in frame' rear spring. Baldwin called it a "quarter elliptical leaf spring" even though it is actually a half or "semi elliptical spring'. The center and 'tail' portion can be rigidly mounted since the leaves in the shackeled end are doing the work - although the force on the leaves is distributed their full length. This "quarter elliptical leaf spring" is typical of steam locomotive engineering - which was cutting edge during its time period. The spring rigging and suspension of a steam locomotive is a study in its own right.
BC

[Trainman4602]

Some of the reason for using that set up was to make clearance for the fire box

[Dick_Morris]

We have just started on overhauling the suspension parts of the full-sized Alaska Railroad 557, a War Department WWII Consolidation. It's not directly related to Ken's specific question but within the last few days I've posted several photos, a drawing of the spring rigging, and a couple of sheets of engineering notes on our Facebook page. https://www.facebook.com/557-Restoratio ... 931790950/

The suspension on this locomotive isn't typical for a Consolidation. The engine truck and two front drive axles are equalized but are isolated from the third and fourth drive axles. The intent was probably to make if better handle poor track. Or maybe it was just due to the preferences and prejudices of the Army major project manager who had to approve every specification and drawing.

[NP317]

Interesting.
Most full-sized logging Mikados I've been familiar with had split equalization too, divided between drive axles #2 and #3.
'Must have been useful that way. Especially considering some of the atrocious track they had to operate on.

My model of Polson #90 faithfully copies this split equalization system.
We'll see how well this works when it gets its first track test mid-August.
~RN

[kenrinc]

Thanks to all who replied. This was very educational for me and shows the wealth of knowledge in this group. Dick's drawings show what looks to be a slot in the frame with a pin which I hadn't seen before and then the spring itself just rests in it's "wings". Looks like the Dec has a similar arrangement. Consolidation GM seemed like it was part of the frame itself. But it looks like I have the right idea.

Thank you !!

Ken-

[Dick_Morris]

Dick's drawings show what looks to be a slot in the frame with a pin which I hadn't seen before and then the spring itself just rests in it's "wings".

What I'm seeing is that Patt. No L.S. 48(?) sits like a saddle on the frame and is able to slide fore and aft. Its bottom surface isn't quite at horizontal so the tab will be vertical and fit into a slot in the springs The tab that sticks up goes through a hole in the spring end clip and the spring. It also looks like there is a 1" wide half round piece cast into it locate it into the half-round groove in the spring end clip.

I'm attaching a drawing of a spring end clip similar to Clip No. 9 and a spring with the appropriate slot with the spring end clip installed. These are from the spring rigging shown on our Facebook page. Although the mounting of the spring is different, it looks like the parts are similar.