4/11/16 - Currently Google Maps does not show this field to the public unless an agency specifically requests it. Please let a Trillium staff member know if you would like this requested for your agency.
The "Short identifier" field is found under trip details in GTFS Manager.
Values entered in this field are exported as trip_short_name in the trips.txt GTFS file.
This field should only contain the text that appears in schedules and sign boards to identify the trip to passengers. An example of its use is to refer to specific train numbers like the screenshot below (see 8453, 8458, 8456).
It should not be used for destination names or limited/express designations.
If an agency does request for this field to be displayed to the public, it will appear between the route name and headsign under the trip itinerary (see example below).