The drawing shown above is of a Rock Island 5100. I am looking at the MR Cyclopedia from where the above was copied. The Milw. could not build more Class S-2 Northerns because of wartime restrictions, so they had to order copies of the R.I. design. I believe that the restorer of 261 likes the shield so that's why it is there. I have never seen a Milw. Loco with a shielded headlight.
I wish that a Milw. S-2 was saved and running, but the S-3 is much much better than nothing.
This post is by Dan's dad who hates the shield, but I like the modified flat smokebox front.