Complex sentence: Passengers board from a waiting area in the southern portion of Union Station's old train shed, at street level along Illinois Street, it is co-located with the city's Greyhound bus depot, making this a multi-modal transportation hub, albeit a small one.
Split into simpler sentences: Passengers board from a waiting area in the southern portion of Union Station's old train shed, at street level along Illinois Street. It is co-located with the city's Greyhound bus depot, making this a multi-modal transportation hub, albeit a small one.