Thursday evening at 9:20pm the West Bradford Fire Co was alerted to Downingtown Pike (Route 322) in the area of Bradford Ave for an unknown type fire, while responding, units were advised the fire was on the high trestle bridge. Upon arrival it was determined the fire was actually in the Downingtown Fire Dept local and they were dispatched as well. Apparatus and crews accessed the area from a driveway off Boot Road and began the process of extinguishing two areas of fire. Crews had to access the bridge with extreme caution and limited personnel due to safety concerns on the bridge, which consisted of large holes in the decking, rotted wood, and the height of the bridge, this situation placed our personnel in extreme unnecessary danger. Crews worked until approximately 12:30 to contain and extinguish the stubborn fire due to the creosote soaked lumber and railroad ties, in which water had to be shuttled to the actual incident due to the remote location. Please stay off this bridge, as there numerous hazards that place you, your friends, families and emergency responders at great risk, that would include serious injury and death.