This is 4468 Mallard pictured between Milford Junction and Knottingley.
4468 Mallard the world's fastest ever steam locomotive was returning to the district where it broke the record on 03 July 1938. That record top speed of 126mph (203km/h) after passing through Grantham, Lincolnshire, on 3 July 1938 still stands. 4468 Mallard will be on display near Grantham station on 7 and 8 September, as part of the 75th anniversary celebrations of the record being set. The steam locomotive is normally kept at the National Railway Museum in York.
I managed a little bit of video as well as the three locomotives made their way slowly towards Grantham.