1861 and 1867 are perfect as weeknight games as they can usually be played by 3 - 6 experienced players in 3 hours. The games are staples at 18xx gaming conventions often as a palate cleanser after playing a longer title. What makes 1861/1867 in particular great entry points into the 18xx system is that the two games introduce the different game mechanics in phases. The beginning of a game only has Minor Companies running relatively simple operations and as the game progresses, new mechanisms like Merger Rounds and the National Railway are introduced. They are great games to learn, have a steady but ever increasing trajectory and speed, and pack enough of a wallop to keep players returning to them time and time again.