Railroad Ink Challengeâ„¢ is a quick playing roll and write game for 1 to 4 players. Grab a board and a dry-erase marker and get ready to reach networking nirvana Expand your gaming experience with the super-colored, super-fun, super-crazy Dice Expansions for Railroad Ink Challenge Every expansion adds a new layer to the game, changing it in unexpected ways and allowing new strategies to be explored and mastered, even for seasoned Railroad Ink Challenge players. Railroad Ink Challenge Dice Expansion Engineer Pack. Note: a Railroad Ink core game is required to use the Dice Expansions The Underground Expansion Pack contains 4 dice that you can use in two ways. Use the 4 special dice of the Engineer Expansion Pack in addition to your regular Route dice, and find new ways to score points: Construction (1 die): perform special actions and restructure your networks , Renovation (1 die): modify pre-existing routes and add more connections to them , Separation (1 die): increase the challenge of your games with tricky expansion and its never-connecting routes , and Special (1 die): build Special Routes in a whole new way and score a lot of points