Complex sentence: When the Red Devils were introduced, the interurban business was in a crisis caused by the increased use of private automobiles and buses, which both took passengers and created traffic jams in the streets where the interurban cars also ran.
Split into simpler sentences: When the Red Devils were introduced, the interurban business already had run into a crisis. This was caused by a massive use of private automobiles and buses, which both took passengeres and made traffic jams in the streets where the interurban cars also ran.