Rail Extension for Timberborn is a free utility addon designed to enhance the gameplay experience by introducing rail infrastructure such as bridges and tunnels. This addon allows players to create customized rail systems, offering a variety of options for building both bridges and tunnels. Players can select from pieces ranging from 1 to 6 units long for bridges, which can be combined creatively to form complete structures. Additionally, the addon includes full bridges that span both sides, measuring between 7 to 10 units long, providing flexibility in design.

The tunnel feature further expands gameplay possibilities, as players can connect tunnels from each side, creating lengths from 1 to 9 units. Notably, there is also a version that includes a levee, enabling trains to pass through dams. This addon is a valuable tool for players looking to enhance their building capabilities within Timberborn, adding depth and variety to the gaming experience.