I caught the last part of a show a couple of days ago. It was about the
1942 road built to Alaska. There were a few interesting clippets of D4(?)
in action.

I saw that show too. A gentleman that worked there said they were given R4 and D4 Cats at first, then got D8's to do the major clearing. Those old Cats sure did a lot of work.

What is the tractor from two scenes of pulling something with 2 exhaust pipes through the hood with smoke coming out of both?

Years ago a Co. made up some higher output attachments and it included dual exhausts. I have seen a couple in my time at the dealer but I believe Old Magnet has more info on the high output D8s & if I recall it was a dealer out in western USA that produced the high output tractors.

There Is A Vidio Out Calld The Alaskan Highway Is This The Same You Refer To Some Good Pics In That

My 1H D8 has a single exaust but the guy I bought it from said it had dual stacks but he changed it to single. The hood is cut out for the duals. This Cat is a '39 model so I am sure it was built long before the high output D8. Someone must have put the dual stacks on it just for cosmetic reasons. I will have to look and see if the holes in the hood look like they were hacked. I know the man who owned this Cat 20 years ago, when I see him I will ask some history on it. It seems a little strange because not much else is hacked on it.

I saw that show, too. I'd like to see it again. The dozer with two stacks looks like a TD-18 to me.

That was my point! I was hoping someone else would realize that because someone said they were all ISSUED cats, that it may not have been necessarily true. I won't say I can stare at the body and say its a dual stacked cat, but I would sooner say A-C and IH both built at least one tractor with dual stacks that may have very well been up there.
BECAUSE there is a picture in a book that shows a CLETRAC on a belt pulley running a sawmill on the Alaskan Highway. If my memory serves me.

As I recall when the construction first started they hijacked a few contractors and told them to bring all their equipment and men with them. In that case all types of equipment would have been there. The army got involved later in conjunction with the private contractors.

All you guys that posted above check your private messages.
AJ