Is there a tool in InRoads or Rail Track that will perform a watershed delineation?
The Display Source Areas command allows you to view the areas that will drain to a certain point based on the triangles of the active surface. To activate this command you will first need to add in the Hydrology and Hydraulics add-in. To do this, select Tools > Application Add-Ins. In the Application Add-Ins dialog, toggle on "Hydrology and Hydraulics Add-In".
The Display Source Areas command will now be available by selecting Evaluation > Hydrology and Hydraulics > Display Source Areas.