I lived and train spotted at Skipton in the 1950's. The only ICI traffic that I can remember were the daily Heysham - Teeside ammonia trains. Empty tank trains were worked from Teeside by Newport, later Thornaby, single WDs acquiring a Starbeck J39 or B16 on route. Later double headed WD's from Thornaby were employed. At Skipton the NE locos were detached for servicing and turning, the tanks being worked forward to Heysham by Midland locos. Loaded tanks from Heysham arrived some time later and the Midland loco was detached and the NE locos attached. Departure of the train was spectacular up the steeply graded Ilkley line and the locos could be heard long after they disappeared from sight. No remarshalling took place at Skipton except for the occasional wagon needing repair.
Tony