The engineer and brakeman of a runaway train that killed four people and leveled a row of suburban homes had been cited previously for safety violations, investigators said.

The 69-car freight train carrying a sandy mineral used to make potash jumped the tracks at 90 mph Friday morning when it failed to make a curve along a residential neighborhood. Trains normally slow to 30 mph for the curve.Engineer Frank Holland, who survived the crash, had been cited for exceeding maximum authorized speed while guiding a train on March 31, 1986, and for failing to properly connect brake lines between locomotives on Feb. 13, 1988, said James Kolstad, National Transportation Safety Board acting chairman. Holland was listed as stable with a collapsed lung at St. Bernardine Medical Center.

Brakeman Allan R. Riess, 42, of Bakersfield, who was killed in the crash, had been cited for failing to take action in a case of an engineer exceeding authorized speed on Oct. 7, Kolstad said Sunday.

The conductor of the runaway Southern Pacific train, E.S. Crown of Bakersfield, who also was killed, had no violations on his record, Kolstad said.

Kolstad said NTSB officials would examine the past violations to determine if they contributed to the derailment.

Investigators also considered faulty brakes and possibly overloaded cargo hoppers as possible causes.

Crew members may not have known how heavy their freight train was and may have miscalculated the braking capability during their descent from a 4,109-foot mountain pass, said NTSB spokesman Ted Lopatkiewicz.