Safety Stripes/Patterns

How do you put in safety stripes on a locomotive using GIMP? Do I need to copy and paste from a real image? Also, how can you curve/distort text to make locos?
Safety Strips are usually set on a 45 degree angle and are between 4 and 9 inches wide. To make them simply create these lines on 45 degree angles and layer them on the locomotive.
MR, what you have to do is open the texture file used to make the paint on the locomotive, and change the texture file so that it incorporates the safety stripes. This is a process called "re-skinning", and whether or not it is possible to put safety stripes on a particular locomotive is going to depend upon exactly how the original creator skinned the locomotive. It is possible (though you don't specifiy the KUID of the locomotive you wish to reskin) that the locomotive is skinned in such a way that applying safety stripes is not possible with the skin distributed with the locomotive, in which case you would need to get the original mesh and create a new skin. Many creators, however, are reluctant, if not completely unwilling to share their meshes. And there might be other problems, too. I am a Windows, rather than a MAC user, and it is possible that the mesh is created in a platform which does not run on your mac. Some creators use GMAX, which has not been supported for more than 10 years, though it is still available. If there ever was a MAC OS version, it may not run on the current version of the MAC OS.

What might be faster and easier in the short term, is to try to contact the original creator, and enquire about the possibility of the creator adding the safety stripes you wish to have added. The success of this approach can be higher if you are prepared to offer some compensation, though it is not always necessary. But neither am I guaranteeing that the creator will be willing. Some creators are no longer producing for the game for various reasons.

Whether it is possible, and how to do it, is dependent upon the specific Trainz asset you're trying to re-skin. I have seen assets where it is trivial to add such safety stripes, and others where it is impossible, given the way the original skin was mapped to the mesh. Without knowing exactly which asset you're trying to add them to, it's not possible to say for certain whether it is possible to accomplish, or how much trouble it will be.