The “doomsday scenario” for the future of Chicago’s transit system is coming into sharp focus: a $770 million budget deficit threatens thousands of jobs, sweeping service cuts and a crater in the local economy if a financial fix isn’t found by spring.

Unless additional funding is secured soon, routes that thousands of people rely on in Chicago could be altered or even eliminated as early as next year.

The Regional Transportation Authority, the umbrella agency overseeing CTA, Metra, and Pace, is calling the situation potentially devastating.