Even if you think what you would say is obvious, please add. This is genuinely something I think makes sense regarding local bus routes given the longevity of light rail and how infrequently routes change, but I also suffer from confirmation bias, so I’m hoping for reasons this would be a terrible idea but obviously would prefer reasons it would be an even more amazing idea than I thought.
My mistake, I meant to type suburban rail (S-Bahn) not light rail.
Anyway, light rail is and extremely loose term and can mean a lot of things, up to a „light metro“, but it’s commonly understood to have exclusive tracks separated from roads. A tram (or streetcar) runs on the street.