Like many people who grew up in the 90s, I have very fond memories of playing Chris Sawyer's games growing up. OpenLoco is an open-source re-implementation of Locomotion, a transport simulation game from 2004, primarily focused on railroads. The project is currently in primarily a reverse-engineering effort, re-implementing the game from scratch in C++. As the game structure is quite difficult to understand at times, this has proven to be a nice, challenging puzzle to solve!
While my activity in the project has declined a little, I am still of the lead contributors of the project. As Locomotion sadly never reached the same levels of popularity as its contemporary, RollerCoaster Tycoon, OpenLoco enjoys a relatively small community of enthusiasts. The reimplementation effort is therefore also taking more time than that of [OpenRCT2]. However, we are very happy with the results of our efforts so far.