johnr j:

I believe trainers should advise employers what training they can do and what training is beyond their scope. For training that is beyond their scope, they should be able to recommend to the employer sources that could provide such training.

The best training for specific attachments would be a trainer from the equipment manufacturer who is familiar with the equipment and who has access to all manuals and the manufacturer's engineering department.

If a trainer wishes to become proficient in any equipment that they are not familiar with or have no expertise in, the trainer should attend a training class from the equipment manufacturer for the specific equipment involved.