SAO PAULO, Brazil (AP) _ A train packed with 1,500 commuters rammed another crowded train broken down on the tracks in a poor suburb Friday, injuring 231 people, officials said.

The accident occurred at 7:15 a.m., train company spokesman Marcio Spila said.

He said passengers were treated at hospitals for bruises, bone breaks, scratches and shock.

Spila said the advancing train was moving at about 10 mph, and that the accident would have been far worse had it been traveling faster.

''The train had just left the station and may have stopped in time but slid into the back of the broken-down train in the rainy weather,'' Spila said. No figure was available for the number of passengers on the idled train.

''If the train had been traveling at normal speeds for that stretch of the track there would have been a great tragedy.''

The accident, which is under investigation, occurred in the Maua region of Sao Paulo.

Rail workers in Rio de Janeiro, 300 miles northeast of Sao Paulo, on Friday struck for a third day to protest poor safety conditions and demand a pay hike.

The strike provoked a riot by 30,000 stranded suburb dwellers on Wednesday. Police fired on the crowd, killing one passenger and injuring 45.