Two major characteristics distinguished the 1000-series from the later series cars. On their sides, the cars had two mylar curtain rollsigns, one above a window next to the doors on each end (while the other car classes have a single flip-dot or LED sign above a window next to the center doors). Second, the bulkheads on each end of the 1000-series cars featured windows that extended to the top of the bulkhead frame, whereas other car classes' bulkhead windows only extend slightly higher than the side windows. These cars were the only cars to have curtain rollsigns until about late 1984 as the system grew and they became a liability. During rehabilitation of these cars in 1993, an exterior loudspeaker was added in place of where one of the rollsigns used to be. The cars also received General Electric AC propulsion (same as that of the AnsaldoBreda A650 railcar used on LA Metro), replacing the original Westinghouse cam-control DC propulsion systems, making them the first cars on the system to use such propulsion systems.