Builds a geospatial network dataset from current MBTA GTFS data.
At the moment, this script downloads the GTFS data and runs it through the ArcGIS tool to create a usable network. Future improvements include downloading street data, and actuallyg generating a network dataset.
This code is based on the workflow of the Create and use a network dataset with public transit data tutorial for ArcGIS Pro. The TransitnetworkTemplate.xml document comes straight from that tutorial and I take no credit for it.