Yes, it is in the photos if you look at right photo. Finding a pure side photo is hard to find, but, there are a couple. Yes, it is in the shadows, but, if can zoom in on the front of the front truck and the rear of the rear truck you can see it.
What you took off is a part of the frame that is in what I believe is an oxbow type shape. In other words, from the side of the frame it curves ninety degrees inward, then ninety degrees down, then curving ninety degrees inward again. The plan that I provided is I believe from a "Locomotive Cyclopedia", so it is there.
Maybe these two will convince you.
Look very closely at this photo posted earlier, just behind the stirrup, and you can see how the frame "esses" and goes across toward the other side.
Let me add this,
The cast on part that you took off is clearly not a good representation of the way the frame is actually shaped. Since you have done so much detailing already, I am sure that you can make a new part that more closely represents the "S" shape of the frame .