As others have noted, it will not take this long by the time the line opens.Over one hour to travel only 11 miles. :/
More importantly, the shock expressed by the long time required to travel such a seeming short distance betrays, in my opinion, a misunderstanding of how people will use the line. Certainly some will board at the Interchange and get off at the Union Depot stop; most likely, however, this will be a relatively small number of overall passengers. Most people will get on somewhere in between and get off somewhere in between.
An analogy might help: it's less than 11 miles from Wall Street to the Bronx. A subway ride will take more than an hour. Urban rail systems are meant for moving huge amounts of people very efficiently while requiring little space. It's an upside if it goes super fast, but going super-fast isn't the sole determinant of success.