How much does an 1980's school bus weigh?

I have 24 years experience in public transit. A forty foot transit bus has a GVWR of about 40,000 Lbs while the same make of bus in the twenty nine foot length is about 30,000 Lbs. The bottom line is that it varies a little by model and a lot by length. Even the "short" type school bus is likely to weigh in at 26,000.