If your local transit agencies are supported (or you're able to add them to the upstream library they use to collect this data), Transportr seems like a good ch

If your local transit agencies are supported (or you're able to add them to the upstream library they use to collect this data), Transportr seems like a good choice: https://transportr.grobox.de/ https://transportr.grobox.de/ Sadly, it doesn't cover any of the agencies in the Bay area, so I've had to rely on Transit (transitapp.com) from the Play Store.