The high-density nature of the Circle line service meant that loading times were important; consequently all cars were fitted with four double sets of air-operated sliding doors per side.

The DM cars were slightly longer to accommodate the drivers' cabs, the saloon dimensions in all other respects being the same.

To replace the CO/CP stock on the Edgware Road to Wimbledon section of the District line, a further eleven trains designated C77 were ordered of identical layout.

[5] Equipment as built included load sensing "Metacone" air suspension, rheostatic braking, hydraulic parking brake, pneumatic camshaft control by GEC and Brush DC motors of type LT117, with each Dm car having four motors.

The guard's door controls were in the driver's cab; this eased conversion to one-person operation in 1984, the first LU line to do so.

[6] The stock had a public address system and rheostatic brakes on the driving motor.

Inside, the maple wood flooring was replaced by light grey, grooved, moulded flooring, and the non-cab ends were fitted with windows, to improve visibility between cars and improve passenger safety.

Final withdrawal of the C Stock commenced on 2 January 2013, when the first full 6-car train, 5515+6515, 5519+6519 and 5732+6732, was taken to Northwood sidings and loaded on lorries to be scrapped.

The C stock was completely withdrawn on the Circle and Hammersmith & City lines by 11 February 2014.

[13] On 3 June 2014, the final scheduled working of C Stock on the London Underground system took place, consisting of 5533/6533+5517/6517+5592/6592, operating train 074.

A railtour took place on 29 June 2014 traversing much of the mileage covered by the stock during its working life.