Bike & Coffee is a popular cafe with locations in a few of the Tren de la Costa platforms. The location is unbeatable in the original ticket office, you can take your pastry and coffee to eat on the platform and watch the train go by. On the weekends there is an antique market on the opposite platform so definitely visit on a weekend if possible for the full experience.
Local cycling enthusiasts in the city often spend their weekend mornings cycling out from the city all the way to Tigre and Bike & Coffee, aptly named, is a popular rest stop along the way.