GMC is correct, bus style chassis and getting the noise and heat away from the driver. There were some "FRED" chassis (front engine diesel) built a few years ago but they were never popular and I don't think anyone builds them anymore.
Next time you have a chance also look at how big the Diesel engine compartment is, not really enough room at the front for all that machinery, FRED chassis had a relatively small engine.
Dave & Myra
One day your life will flash before your eyes,
make sure it's worth watching!