The images is of a High Speed Train, lead power unit number 254 018 (I believe the trailing power unit would be 254 019), which is in British Rail Intercity 125 colours. The first image was taken from Aislaby Road bridge as the train was approaching Yarm viaduct, and the second as the same train started to cross the viaduct. Probably early 1979.
Photographs and details courtesy of Alec Moody.
High Speed Train I wonder what the top speed was in those days. I had the pleasure of travelling on the Chinese version of the High Speed Train recently and it clocked up at 434 Kilometres per hour of which I have a photograph of the speed clock that was in all of the carriages. When you think of the famous fighter planes of the second World War they were travelling at speeds about the equal to this speed… I think the flying Scotsman Train which regularly travelled through the North East held the World Record for many years at I think 137 Miles per hour. How things have changed in the last twenty years.