Complex sentence: There are also claims stating the original T1s operated at higher operational speeds than the official recorded speed held by "Mallard", going as high as 140 miles per hour with fully loaded trains.
Split into simpler sentences: There are also claims stating the original T1s operated at higher operational speeds than the official recorded speed held by "Mallard". It has been reported that PRR T1 locomotives were capable of achieving speeds in excess of 140 miles per hour with fully loaded trains.