These have a very wide firebox and even though I am using gas, I was still worried about the red paint on the sides, so I cut two of these out and dropped them in through the slit between the boiler and the walkway
The steam line keeps the other one in place and I just stuck a strong magnet to the other one. So far the heat hasn’t affected the magnet enough and it’s keeping in place and the paint still looks perfect.

Here’s the underside of the boiler for those that haven’t seen them on these engines.
