Detroit Timken made a 2 speed axle, but I'm not sure if they ever made a 2 speed tandem. Here is a diagram of Eaton vs. Timken tandem units. The Timken which later bacame Rockwell and now is Meritor used a through shaft. The 1950's Eaton had the interaxle driveshaft above the forward axle. This design didn't last very long. In about 1960 Eaton went the through shaft design that is the standard of the industry today.
As for the tires, the wheel I see on the drive shaft is a lock ring style that is relatively safe. It is still produced today. On the drive axle, the lock ring are on the inside and couldn't go anywhere even if a lock ring were to blow off. You have to be more careful with the steer tires. The lock ring is to the outside. If it is not properly seated, it can be dangerous. I run all tubeless tires on my fleet and have been for over 40 years. But I have been messing with tube tires for over 60 years. Here is a photo of my latest toy. I put just enough air in the steer tires that they stood up and then towed the thing 70 miles per hour in 100 degree weather. Unless the tires have been totally flat for years, bias tires are less likely to blow than radials. It was running them so slick that they wore down to the tube or running over a sharp rock that caused the old bias tires to blow.
