The following are utilities that are available to all for free:
Conbuilder - Indespensible - It is very usefull to create consists and edit one you already have. It is very easy to use. It also is very usefull in finding errors in eng/wag and consist files.
It only has two drawbacks - but they are not big ones. 1. It only uses a generic outline of an engine or car. If a jpg or gif picture of the stock is not in the stock's folder, it will not show a piture when you right click on it. 2. It does not calculate the consists volcity/acceleration numbers, it uses generic. This can be fixed by opening the consist in the AE and flipping an engine backwards, then flipping it back and exit with saving.
Route Control - This can be a usefull tool for finding errors in different files. It is quick, that is it's main feature. It has been surpassed in usefullness by Route riter.
Route Riter - another must have. It can do everything the others do. This is the single most powerfull tool for MSTS.
EngMod - another must have. This enables the user to edit ALL the eng files at one. You can edit all the wags at once also. This is great for fixing coupler damping and break lines without haveing to edit the files one at a time. It also has a bracket checking feature.