[4] It was originally classified as a Class 150, but was reclassified into the departmental series.

The unit is formed of two driving motor vehicles, numbered 999600 and 999601.

The unit is currently painted in a plain overall yellow livery with Network Rail branding.

In December 2024, Network Rail announced that the unit would be withdrawn and scrapped, to be replaced by additional (modified) Class 153s.

[5] Media related to British Rail Class 950 at Wikimedia Commons