Complex sentence: An accident furthermore delayed the introduction of regular top speed services, as on 1971-07-21 the AFB on 103 106 was suspected to be responsible for accelerating the train out of control, resulting in a derailment with 23 dead and 121 injured.
Split into simpler sentences: An accident furthermore delayed the introduction of regular top speed services, as on 21. July 1971 the AFB on 103 106 was suspected to be responsible for accelerating the train out of control, resulting in a derailment with 23 dead and 121 injured.