How to make a .TgPcDx file invisible

I've got a file for a very old (RS) UK emu that has a "shade" texture that floats over the track. The model runs fine in TSC 2024; there's no problem there. But that shade file looks just awful. In the old MSTS days I knew how to export alpha channels of ace files and modify same with black paint to allow something (for example, cab windows) to be visible. In the case of this shadow file, I don't want it to be visible, I want it to be transparent.
I read Buzz's tutorial on using DXTBmp and RSBinTool to modify TgPcDx files and it the instructions worked fine: I had no problem modifying a cab side, for example. But the instructions assume that the alpha file will remain the same. So my question is twofold: 1. Do I take the "shade" file and delete all of the pixels leaving a blank file. 2. Then do I modify the alpha channel so that the blank "shade" file literally becomes invisible?
Thanks for your thoughts!
Dave
I read Buzz's tutorial on using DXTBmp and RSBinTool to modify TgPcDx files and it the instructions worked fine: I had no problem modifying a cab side, for example. But the instructions assume that the alpha file will remain the same. So my question is twofold: 1. Do I take the "shade" file and delete all of the pixels leaving a blank file. 2. Then do I modify the alpha channel so that the blank "shade" file literally becomes invisible?
Thanks for your thoughts!
Dave