 Traction control equipment was by GEC, with the batteries supplied by DP Battery Co Ltd. As with previous batches, parts of the locomotives were refurbished; in this case, the bogies, traction motors and compressors were supplied by Acton Works.Unlike earlier models, each vehicle was fitted with two compressors, allowing them to work singly.The last steam engines were withdrawn soon afterwards, and an order for five more battery locos was placed with Metro Cammell in 1969.