The TRAINS project is a long-term effort to build a system that can interact and collaborate with humans in problem solving tasks, combining situation assessment, interactive plan construction, evaluation and execution. TRAINS-95 is an instance of the general architecture for mixed-initiative specification of routes using a simple map. The system is robust and can be used by novice users to solve problems with essentially no training. Over 50 different people have used the system so far, with a large percentage of them successfully completing their assigned tasks. This paper considers the TRAINS system as an embodied natural language system.