Are you a developer looking for a Caltrain real-time API?
The Metropolitan Transportation Commission provides the Caltrain real-time data to third party developers via their 511 Real-Time Transit Departures API (beta)

Are you a developer who would like to create a Caltrain timetable app?
To download the latest official Caltrain GTFS file, all developers are required to fill out the application form HERE.

Latest GTFS Updates - (Subscribe HERE to receive GTFS Update email notifications)
4/3/2014 - Corrections to Bullet Train on 2015 President's Day.
- Added College Park stop to Train 159.
- Saved shapes.txt file as ANSI.
3/28/2014 - Updated coordinates for NEW San Bruno Caltrain Station and platform stops.
2/13/2014 MAJOR UPDATE:
- Added use of platform_code in stops.txt
- Correcting adjusting stop locations with respect to "stations"
- Corrected routes.txt file to use route_long_name instead of route_short_name
- Corrected routes.txt to have route_type = Rail
2/7/2014 NEW Hastus Generated GTFS of schedule effective October 2012. Includes President's Day 2014.
7/23/2013 Update to trips.txt: Start using trip_short_name column. Remove (Train ###) text from trip_headsign. Add remaining holidays for 2013.
12/20/2012 Removed extra fare attribute causing incorrect fare quotes.
11/28/2012 Corrections to the calendar_dates file which defines holidays.
10/05/2012 ISSUE: "trip_id" for Train 277 is set to 275_20121001 in the GTFS.
ANSWER: Our feed developer has checked the data. Although there is a discrepancy between the trip_id and the trip_short_name, it is not causing a referential integrity error as Google Transit is able to pull up a valid itinerary for this train number. An immediate update is not required. Since the feed is still fairly new, we will update after we receive more feedback from developers and users of Google Transit.

For General Transit Feed Specification information, go HERE.

4/3/14 - rjc