Lets go into what you will need to start.
FIRST. You will need a program to modify the skins. There are some for free like paint dot net (paint.net). Ive heard good things about paint.net and from what I understand its easy to use. I dont think that MS Paint (the one in your accessories under start) has enough capability to do good reskins, but it can be used.
I prefer Adobe Photoshop because I'm used to it and have alot of experience with it. The range of abilities it has is tops. The drawback is the pricetag for the software, hundreds **unless you know how to download torrent files ;) **
SECOND. Learn how to open the content and clone it before starting. Cloning enables you to make an excact copy of the item with your username. You want to do this so you don't ruin the original item if you mess it up. In the event that you mess up your cloned item you can delete it and clone the original again. If you modify the original and ruin it, thats it. No object to clone to start over.
So lets get started on what has to be done to clone an item in Trainz.
First Open the game and go to the CMP (manage content)
Find the item you would like to modify (you must have the item downloaded already to clone it). Right click on the item and select clone. Then select "veiw in main list" Its that easy. Now you have an excact copy with your user name as the author.
THIRD you need to open the item so you can edit it. Now you right click the item and go to "edit" then "edit in explorer"
Do not touch the config file. You can mess the item up that way. We'll go into that later.
OK now what is one of the hardest parts of reskinning. Since there is so much content and so many different people making it, it is all laid out differently. What you want will be in one of the folders you see when you follow the above third step but which files in which folders will be up to you to figure out. Take for example the Horizon coaches made by Magicland. The files for the skins are in the "Horizoncoach_body" folder. Alot of the content will say things like "body","shadow","art","alph numbers". In most cases it will say something like "body". Thats where the skin files are.
You will have to figure these things out as you go along. Open the folder and you will find many files in it usually. YOU DONT WANT TO TOUCH THE ".im" files or the ".txt" files. You only need to open the art files which are usually .TGA, .BMP, or .JPG files. You will have to open these files with your paint program and go through the files to see what you want to change.
Now the HARDEST, I mean HARDEST part of reskinning. Finding what areas of the skin file goes where on the item. Some things are easy like in the Horizon coaches the red and blue stripes are obviously on the passenger car where the windows are. But more times than not I find myself painting unknown areas neon colors, then veiwing the item in the railyard to figure out what neon colored items are where on the train. Its VERY time consuming but nessesary to do the skins. Thats often why simple reskins can take hours of time to complete.
Last. Lets assume you found what you were looking for and you are complete. You now have to save the new skin with the same name as the one your replacing. The name needs to be EXCACLY the same or the game will not be able to find your new skin. When it asks you to replace the file answer yes. Now close the files out. And now your back to CMP. The item that you are working on now needs to be "comitted" in order to use it. You can left click on the item. That should highlight it in blue. Now press the Ctrl and the "M" key. It will say "commiting changes". When its done, thats it. You can now veiw your newly painted item in the Railyard part of the game.
Now the renaming of the item. You will have to follow all the same steps as you did for reskinning only this time you want to open the "config" file. Double click the config file. Scroll down till you find the phrase "username"
To the right, in quotes you will see the name of the item. Change the name in the quotes to whatever you like. Be sure to write in between the quotes only. Then X out. When it asks you to save changes click yes. Then follow the directions above to commit the item again. When it commits your new name should be there. BE WARNED if you decide to mess with any other items in the config file be prepared to have your item not work. Unless you know what your doing leave the rest of the items alone.
Like I said these are the basics. To go further into the processes would require alot of time on my part. Time I do not have. I beleive experience is the best teacher when it comes to modifying content. As you do more you will learn more.
To contact me just click the "Contact Us" part of the site here. You can ask anything except request items on this site.
To learn more join Trainz Commuter Rail website at: http://trainzcommuterrail.co.cc/site/
Theres alot of people there willing to help.