Much of the crowd, which jam-packed Penn Square this morning to see and hear Sen. John F. Kennedy reacted like screaming fans of a rock ‘n’ roll singing idol. When the democratic candidate for president arrive at the speakers’ platform on the northeast of 5th and Penn Streets, the crowd – estimated up to 30,000 – broke through the police lines and mobbed the officials’ area. They broke through flimsy rope barriers which city police had erected and brushed right past more than 25 city police, 15 state troopers, uniformed deputy sheriffs, county detectives and other police officials to get as close as possible to their hero of the day. It was the teenagers who gave Kennedy and his party the biggest massed scream. The older folks in the audience just cheered and applauded.