The train derailed, and about 30 passengers were killed or injured.
Literal
Train [subject-が] derailed, about 30-people [of-の] passengers [subject-が] were-killed-or-injured.
脱線する is the dedicated verb for trains derailing. 死傷する is a dense news-report verb combining 死 ('death') + 傷 ('injury') + する — literally 'to die-or-be-injured.' Reading: ししょうする. This kind of compact Sino-Japanese verb is characteristic of news writing.