From the Lagoon of Liquidspaceman...
I love the idea of adding fog somewhere in, or around HM.
It got me thinking, why not have some sort of Diorama scene in the train tunnel? It would be kind of cool to have the train go over a Louisianan bog with the cemetery off in the distance, using forced perspective, and of course fog. The fog would be either off in the distance or you would go through it only temporarily and wouldn't "hurt" any AIs. Since all graves in New Orleans are above ground, do to the water table height, it could be an awesome view from the train by "peeking" into a new part of the HM ride only seen by guests from the DRR.
...Liquidspaceman, over and out!