تَأَخَّرَ الْقِطَارُ. تَعَطَّلَ الْمُحَرِّكُ. وَالْمُسَافِرُونَ يَنْتَظِرُونَ. الصَّبْرُ عِنْدَ الشِّدَّةِ حِكْمَةٌ.
The train was delayed. The engine had failed. The passengers were waiting. Patience in difficulty is wisdom.
If the delay raises a natural question about its cause, the second clause can function as explanatory resumption. The third may depict a concurrent state, hence a circumstantial clause. The closing maxim comments on the situation and endorses an appropriate response to it.
A single passage need not instantiate one device throughout. Analysis should establish the discourse relation at each boundary and specify the evidence for the proposed interpretation.