So I created from scratch a working ash pit. I didn't take the most pictures during the step by step process but I love the out come.
How I did it. I cut out a area on the layout, cut plywood to make the pit a 2inch drop from the top of the layout. The inside walls I made with strip wood that I stained. I used a hole saw bit to cut a hole for the funnel to the smoke unit. For a smoke unit, I used a MTH proto 1 fan driven smoke unit that I hooked up to a transformer that I use for accessories. The funnel is small that I got to fill flask with, that I attached a piece of brass tubing to lead to the smoke unit. The actual ash cover. I took a model car acrylic case cover, that I cut and glued back together to make the size I needed. The biggest ash pan on my biggest locomotive is about 3.5inches so I made the ash cover 4inches. Drilled a bunch of 5/16 holes in it to let smoke and red light out to simulate that the ash pan has been dumped. There's 2 red Woodland Scenic LED's under it. The front facing edge I left uncovered so more red ash glow protrudes through. That cover can be taken out and I fill the smoke unit with a needle applicator.
