Lionel 2032 Alco rear replacement steps problem

There are no flathead screws.
The frame casting has a couple of studs molded right in place.
The steps are placed over the studs, and the end of the stud is splayed

I do not have time to explain how to replace the steps right at this moment.
If nobody does it first, I will explain when I return.

(it's always possible that the steps were replaced using screws in the past, but that is not commonly found)

Well, that is very helpful.   I do have a visual impairment so maybe that's why I can't get them off since I'm seeing flathead screws where none exist.  Yes, it would be great to have more detailed information from you or someone else, thanks

How about a picture of the area? As CWB says the normal way is without screws for die cast frames.

I have some on-line work to complete for my company but after that I will take some photos and post them. 

Does it help to take off the body and try to loosen them from above? 

First: I'd encourage you to remove the body any time you are working on your locomotive. No point in adding new boo-boos to a sixty year old shell.

You might need to remove the truck that is closest to where you are working.

Usually the remains of the original steps can be gently pried away from the casting by sticking a small screwdriver between the sheet metal and the frame. I do it on the inside corners, near the bosses. If it takes more than gentle pressure, you may need to grind away some of the boss. I would use a Dremel. I often use the edge of a cutoff wheel as a grinder. Be aware that they are very brittle. Wear goggles. I have many years of practice doing this without shattering the wheel.

Usually there is enough of the boss left to pop the new steps over it.
Support the top side of the frame. I put a piece of felt between the frame and it's support to avoid marring.
Use a 1/4 inch cold chisel and a small hammer to  re-splay what's left of the boss.
You don't need to hit it too hard. Either there is enough metal left, or there isn't. Hitting the chisel harder isn't going to help.

If there isn't enough of the boss left to re-splay, then scratch up the side of the replacement steps that comes in contact with the frame around the boss, and use a very small amount of CA glue to hold the step in place. I think I would use a gap filling CA glue. When it comes to CA glue, I go for the stuff sold in my local hobby shop. I never had much luck with the bargain stuff.

This picture has the spots I'd use to pry off the old steps circled in red

I understand what needs to be done now. Thanks again for taking the time to walk me through the process.