Before using LocoTools it is recommended you back up your Locomotion .DAT files found in the ObjData folder. You can then restore the original version if you have any problems.
Downloading & Installing
You can download the latest LocoTools version from http://www.ttdpatch.net/loco/. I then recommend putting the unzipped files in a seperate folder in the ObjData directory. You will create alot of files and it is best to not mix them in with your .DAT files. Remember to keep the .dll with the executable or it won't work.
To decode your DAT files into an editable format, copy them from ObjData to your LocoTools folder and then simply drag the file onto the LocoTools executable. It will then create an .XML file in that directory and create a new folder for the images. The XML file contains all the variables for that object, such as cost and name, whilst all the graphics used by that object are stored as individual .PNG files in the seperate folder.
When you are happy with your changes, you can simply drag your updated .XML file onto the LocoTools executable. It will create a backup file of your old .DAT and create a new one for you. Simply drop this file into your ObjData folder and when you next run Locomotion, it will update itself with the new objects.
If you are having problems, make note of the error message and use it to fix the problem. To avoid problems, ensure you have all the graphics files properly numbered in relation to the .XML file. Even if the graphic is not used, it needs to be present, but you can shrink it to a single transparent blue pixel to save on file space. If the problems persist, restore an old backup file.