 Complete the following phrase:  In February 1850, the PWB improved its Baltimore terminus by completing erection of a new station, with a 208-foot 63 m barrel-vaulted train shed. Service onward to Washington, D.C., was facilitated by drawing the coaches by horse down Pratt Street to the BO terminal, first at East Pratt and South Charles Streets, later after 1857, to the new Camden Street Station. In 1861, one week after the American Civil War began with the Confederate firings on Fort Sumter, in Charleston harbor, in South Carolina, an angry mob of Southern sympathizers attacked a trainload of future Union Army soldiers of the 6th Massachusetts volunteer state militia, joined in Philadelphia by the Washington Brigade of Pennsylvania state militia, heading to Washington to protect the Capital and respond to President Lincolns call for 75,000 troops and declaring a state of rebellion. Because locomotives were not allowed to transfer through the city possibly for fire safety reasons during their transfer: the First Bloodshed of this famous 