What is an S file?
An S file is a generic 源代码 file that contains the source for a computer program. It may be written in a number of different programming languages, but is commonly used for storing Assembly code.
If you find an S file and do not know what programming language it contains, you can open it using a variety of text and source code editors. Some programs that can open and edit S files include Microsoft Notepad, gVim, MacroMates TextMate, Bare Bones BBEdit, and Vi.
.S File Association 2
Shape file used by Microsoft Train Simulator, a program that allows users to play the role of a locomotive engineer or passenger; contains shape data such as geometry, images, size, texture, and lighting effects; used for customizing and displaying locomotives in Train Simulator.
S files can be used to "tweak" new locomotive graphics that are added by users. They can be generated using the "Conv3DS" program with .3DS files in Train Simulator. Once an S file has been generated, it may be edited using a text editor.