Problem in Implementation of Tree Observation
In the file observations.py, in class TreeObsForRailEnv , in function _explore_branch (line no. 298 , 307) ,I think there is problem in other_agent_same_direction update.
other_agent_same_direction should just be incremented by 1, since one cell can hold only one agent at a time, and its direction is same as the direction in which we are exploring.
other_agent_opposite_direction should not be modified.