even for a vehicle driven in service essential to the war effort!

It looks like they posed a new tractor and trailer for a marketing shot. The truck has no mudflaps, air lines or electrical pigtail going to the trailer. The tires are pristine.
Not a lot on Federal trucks out there. I think it's probably a 45, 60, or 65 model. The louvres match. I can only guess that the 600 series were twin screws, while any two-axle tractor had a two digit model number, even if ordered with a tag axle.

The sides and rear of the truck have the old style "cat's eye" reflectors, with glass spheres in a round holder. I am pretty sure the ones on the rear (between the electric lights) and the ones on the sides at the rear (under the marker light) would have been red; I don't know if the ones on the sides at the front would have been orange or red back then. The letters on US Interstate signs used to have a similar type of reflector.

The next development was a relatively flat plastic reflector; the back surface of the plastic has little molded cubes set at an angle. (Most cars have these today, somewhere in the rear light lenses.) The next development after that was Scotchlite tape, full of tiny glass beads; that tape is ubitiquous on semi-trailers today.

It's also interesting that the middle ladder has a lower step and a step pocket in the side of the trailer. For the front and rear ladders, I guess the plan was that the driver could climb on the wheel and tire. Today, there would probably be some kind of extension of those two ladders as well.

The Reliance name is still around. It looks like the original company shut down in 2010 and was bought by another company, Cozad, who still makes trailers under the Reliance name. They are still using the same cast outline badge under the rear bumper.

The rearmost axle on the tractor is a tag axle. Its wheels don't drive, they only carry weight.

I'm thinking that air brakes weren't thought of as reliable as regular brakes in those days.

[It's the other way around. The message is a warning not to follow too closely because "this giant tractor-trailer stops faster than you might expect." Also exhaust from the pressure-relief ports at the rear can kick up dust and gravel, and makes a loud noise. - Dave]

Can any truck experts tell us why air-braked trucks used to have this warning on their rear? (I've driven trucks with air brakes since 1990 and they're essentially the same as hydraulic brakes as far as other traffic is concerned).

Here's a Federal Model 60 tandem, which looks very similar:

Nice rig! Carried 5,000 gallons milk appx. I wish I could see the nose of the tractor. Possibly a White! Double over drive shifter. Old school shifting system in it!

It looks like one of the "600" series Federal tractors because of the twin axles. Can't tell because I can't see much of the truck at that angle.

Going by the general shape and especially by the hood louvres, I'm going to say it's a Federal Model 45.

Edit: On second thought, I'm not too sure about the model. It's a Federal, but the 45 seems to have only one rear axle. Possibly a 606, if there was a civilian version of the 606. NOT a truck expert!

Can't help with the truck, but Marin Dell's wonderful Art Moderne plant building is still there at 1675 Howard St., currently housing a BMW dealer. (I drank Marin Dell milk all the time as a kid, btw. Well, except when I wasn't drinking Lucas Valley.)

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