I messaged SLI/TS in April of 2020 with an inquiry into whether they can eventually introduce a blank texture pack for their newer products (such as the rolling stock for the Seligman Route or Mullan Pass route) or otherwise revamp discontinued products with better integration and compatibility with OR-only features.

They said they have no plans at this time, but eventually they might have free time.

However, I'm not intending on asking for one too many favors. I'm not endorsing anything that could jeopardize their trust... All I'm doing is a suggestion to create a texture pack with documentation stating which Shapes to use, which Cabview and Sounds to use, and how to work with Shape File Editing just to keep all newly-created Engines in one directory. That way new people can learn and get their minds and skills adjusted for this new era of simulation...
Cheers and Have Fun,

Zach Bell | SkallySims