The unique Class 950 track recording unit 950001 was constructed in 1987 using a modified Class 150 bodyshell. Unfortunately, I never saw it in its original livery, which was standard BR blue and grey with a wide red mid bodyside stripe. It mostly continued to elude me in this later Railtrack colour scheme. Naturally after it was painted all over yellow, I have seen it on many occasions! Here it is passing New Barnetby on 8 December 2001.