Downloadable content (DLC) is additional content created for a released video game. It is distributed through the Internet by the game’s official publisher or other third party content producers. Downloadable content can be of several types, ranging from aesthetic outfit changes to a new, extensive storyline, similar to an expansion pack. As such, DLC may add new game modes, objects, levels, challenges or other features to a complete and already released game. DLC and a content creating and sharing user base are essential long-term needs in more complex simulator products such as V-scale model railroading applications (such as Trainz, RailWorks, and MSTS) where in the long term, much of the allure comes from the ability to build new layouts or expand others, including writing customized the “game play” like operating modules. Since 3D asset generation is typically a technically demanding and time consuming activity—a steam locomotive can take 2–4 full months of time to implement, and a long large route can consume years of development—such emulations only grow through the power of numbers of the many producing and sharing assets in the hobby community. In the case of episodic video games, a new episode may come in the form of downloadable content, whereas music video games utilize this media to offer new songs for the players. Downloadable content became prevalent in the 21st century, and especially with the proliferation of Internet-enabled, sixth-generation video game consoles. Special edition or Game of the Year re-releases of games often incorporate previously released DLC along with the main title in a physical package.