The CTA instructor was crammed into a seat on the back end of a snowplow paused on the tracks when he saw the Yellow Line train round the curve headed toward them that November day nearly a year ago.

The legal limit for train operators is .02. The crash caused $8.7 million in damage. The CTA Yellow Line-Skokie Swift did not resume operations until January 2024 — seven weeks after the crash.

Over the past five years, slow zones have grown along most sections of the train system, the CTA slow zone maps show. One area that has slowed notably is the Yellow Line, where speeds were ...