A three-alarm fire broke out at a three-story, single-family home in Newton this evening, according to the Newton Fire Department. At 6:21 p.m., the department reported that neither civilians nor firefighters had suffered any injuries from the heavy fire at 355 Newtonville Ave., but had not yet confirmed whether the fire had been put out or cited a cause for the fire. All three Newton ladder trucks worked to put out the heavy blaze. Firefighters from Boston also joined in the effort to douse the flames. Massachusetts States Police reported the fire caused traffic backups on the Massachusetts Turnpike early Saturday evening.