Hello,
I think the question was not yet answered so i want to raise this again.
I think the (corrected)question is, what are the rules if the erv in the active has modal verbs (ex. can drive, can speak):
"Le train n'a pas été pu arrêté à temps par le conducteur." - Wrong
"Le train n'a pas pu être arrêté à temps par le conducteur." - Right
Based on above, rule should be
1. Take modal verb - change to corresponding compound text
2. Add infinitive être
3. Add past participle of the other verb (ex. can drive)
Is above understanding correct, can this be added in this dicussion or have a separate discussion