tmcw/wmataapiapi is an open source project that you can use and help

wmataapiapi

An API on an API on an API, designed to fix artificial scarcity of transit data in Washington, DC.

This api is free to use in any way you know how, but if you want to use it a lot or rely on it being up 24/7, you should host it yourself, like a champ.

// list all rail stations
/rail/station
// a specific rail station predictions
/rail/station/:code
// all bus positions
/bus/position
/bus/position/history/
/bus/position.geojson
/rail/station/:code/prediction
/rail/station/all/prediction

don't get it? here's one thing you could make with it.