British Railways built over 1000 insulated fitted 'Insulfish' vans in multiple batches in the 1950s and early 60s. Of nominal importance were the Blue Spot fish vans, retrofitted with roller bearing axleboxes for high speed running to express timings across the ECML. Some such vans were branded 'TO WORK BETWEEN ABERDEEN AND KINGS CROSS ONLY', although it wasn't uncommon to find such marked vans elsewhere on the railway!
This 12T Insulfish van is in the later 'ice blue' livery, built to diag. 800.
Thanks to Frank (borderreiver) for research and reference material. The JAG System developed by Kessica is a script library being used for the lamp handling effects and ACS Coupling.