Hiawathamr Trainz Add-ons is an independent Trainz content brand run by a solo creator, specializing in route and session development for Trainz Railroad Simulator 2019 and 2022, Trainz Simulator 3, and newer versions of Trainz. Its catalog includes payware routes in small, medium, and large formats, model railway routes, and sessions and other supplementary items. Visitors can also find freeware routes and miscellaneous content, along with selected third-party offerings.

The site features themed releases such as City and Country USA mission packs, which add sessions and new content for players to explore. Beyond downloads, Hiawathamr provides announcements and content news, a knowledge base, and community forums where users can follow works in progress and access additional previews. The brand also directs visitors to SRS Trainz, a sister site that hosts its separate SRS Trainz content collection, including North American, UK, and other content.

With resources organized for different Trainz versions and interests, Hiawathamr offers simulation enthusiasts routes, activities, and supporting community information in one destination