Input (grade 13): They were initially classified as AM3 units before the introduction of the TOPS classification system, and were the dominant EMU on the Glasgow suburban railway network for over 25 years before being progressively phased out by newer rolling stock.
Output (grade 9): At first they were classified as AM3 units before the introduction of the TOPS classification system. They were the dominant EMU on the Glasgow suburban railway network for over 25 years.