They are both CHAMBERLAIN, the yellow tractor is about 1980 model 4280 John Deere engine about 116 HP. It had done about 11,000 hrs. The FEL tractor is about 1973 model 306 with a perkins engine about 69 HP. I am a little vague but John Deere bought Chamberlain out in the early 80s, I think they only made one more model after the 8280 and that model they painted with there green and that only lasted to the mid 80s. I think that chamberlains were the only tractor manufacture that built there tractor on a chassis this enabled major repairs to be done without spliting the tractor.
During the 70s i drove these tractors with big heavy buffer plates welded to the chassis as shunt tractors pushing and pulling railway carrages. We would push and pull as many a 15 of these carrages at a time fully ladened each weighing any were up to 90 tons.
So in total i would have put in sumwhere around 30 or 40 k hours on Chamberlains. the greatest tractor ever built, at least that what i think.