The 28-50 is a strong, powerful tractor designed
to carry out the toughest jobs. It's large four cylinder engine was similar to the 22-40
but in this case two 12-24 engine blocks are used with a 5.75 inch bore. 
It had a surplus
of power. In the Nebraska tests it performed a hefty 46 h.p. on the drawbar and a whooping 64 h.p. on the
belt. It had substantially more horsepower than it's given rating. Even though Hart-Parr doesn't make mention of two styles of 28-50's there really are two styles.
The two styles are simply the narrow radiator and the wide radiator. The reason for the two different
radiators is simply that the narrow or smaller one had cooling problems so the radiator
capacity was enlarged on the wider models for better cooling. And another visible difference
is the heavy cast eight spoke rear wheel on the early models and then the flat spoke rear wheel of the later style.
Starting with the early model 28-50's a cab was available as an option. It really wasn't an
enclosed cab rather just a roof over your head to keep the sun and rain off of the operator.
It is rather impressive to see a 28-50 with a cab and listen to the engine operating a sawmill.
A two forward speed transmission remained throughout the 28-50 production.