[jeffbee]

This is a problem with GTFS. Firstly, that GTFS has separate enumerators for trains vs. buses, and only shows stuff that identifies itself as trains, but also because most agencies do not provide route shapes that are good enough to display. Often the routes run right down the centerlines of roads, cut through buildings at corners, etc. There would have to be a revolution in local government agency GIS quality control before it works right.

[TulliusCicero]

I feel like Google itself could probably clean up the route presentation, given their own understanding of the roads.

[jeffbee]

Technically it sounds feasible, but they'd want to avoid being accused of undermining the open data of the GTFS ecosystem.