Since the company does not have a certified S.O., the Model S.O. would apply. I have tried to verify the IE SO Bombay Act but could not download it from the net. However, in the Model S.O. of Central Rules, the classification of employees speaks only of Apprentices; there is no mention of company trainees. So, despite its absence, can a company still have Trainees is a moot question to be answered.
Types of trainees
There are two types of trainees: one set of trainees are trained for further absorption in the company, more used for Management Trainees, and the second is those engaged on a year-to-year basis and after the training is over, they leave, mostly technical trainees. In case you would like to adopt the latter course, have a clear-cut policy and training manual; appointments have to strictly follow the training schedule, and the end date specifically mentioned and followed. It is seen that many organizations take trainees with the avowed purpose of imparting training, but they are used in regular production jobs, their appointment periods get extended, finally after the lapse of a sizeable period you have a problem in hand, neither they can be terminated nor you want to absorb them. Beware of this pitfall. Speaking from my experience, in addition to Act Apprentices, we had certain Company Trainees taken every year and trained them as per the curriculum, and they were let off after training, but our Certified S.O. had a provision for it.