SFM automatically creates a .bak file when you modify a shape. If your model disappears in the sim after an edit, simply delete the corrupted .s file and rename the .bak back to .s .
The longevity of MSTS and Open Rails relies entirely on user-generated content. However, modifying preexisting 3D models has historically been difficult because MSTS compresses .S files into a unreadable binary format to optimize engine performance. msts shape file manager 25 hot