they were mostly an industrial engine, and in the largest trucks - you can find more info on them at Jolly's site, at the bottom of the page is links to more pages

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics