Create your own train is an Addon for MCPE, it has a unpainted train replaces the minecart. It's also allow you repaint the train in the addon file. But I will only allow you to do that for private use. You will need to PM at my instagram @dpr.glodelania if you want to publish your costumized train or if you wan to use it on a server. There is a txt file that gives you some instruction how to paint the train rightfully and some restriction like don't edit or reshape the windows, wheels and doors unless your you're a pro-pixel artist and pro at editing the model file.
The reason why I created this addon is to create more train addons easier.