Slower speeds, fewer round trips, less ridership and budget shortfalls are projected if existing rail through Hall County is chosen among three options for proposed Atlanta-Charlotte, N.C. passenger rail service, a report issued by state and federal officials shows. The historic Southern Crescent route would have the lowest costs to build, at $2 billion to $2.3 billion, depending on projected train speeds. But otherwise, the route would accommodate only four round trips, compared to as many as 22 on one of the other routes under consideration for the service, according to a report from the Georgia Department of Transportation and Federal Railroad Administration.