The height restrictions cause unnecessary scrolling on desktops when there are many alerts or when you've clicked on gallery place / metro center without any filters. The height restrictions currently exists to prevent screwy layout stuff on mobile but using a media query that can be fixed for desktop.
Some train icons (teardrops) have black outlines (silver, orange, yellow). Others have white outlines (blue, red, green). They should be consistent. Probably no outline would be best.
https://www.dcmetrohero.com/apis
The MetroAlerts API provided by dcmetrohero has station codes associated with each alert (unlike WMATA's API). Evaluate the accuracy of this API and come up with a way of displaying affected stations.
Right now I fetch all trains, alerts and predictions no matter what filters you have set. This is great when on a desktop or wifi since you get really snappy results when toggling filters on and off. But it's not so great for mobile users who have limited data. Add a toggle to only fetch data that is immediately needed.