Joe,
I learnt that 70-ton Protocraft trucks were the appropriate trucks for this Husky car from another forum member after I documented the conversion with the 100-ton trucks on this 2-rail forum. I bought the 100-ton Protocraft trucks to use on MTH coalporters but after I decided to narrow my interests to modern intermodal I sold the coalporters (& other cars) & had to find another use for the trucks that I had.
I have the Trinity cars but they were bought as 2-rail & I didn’t look at the truck mounting scheme. But if it is similar to the other Atlas Masterline & Trainman cars that I owned, then there must be a cast-in pilot with screw threads on the underside of the cars which needs an oversize hole in the truck bolster. Atlas trucks are just right for this design. You might need to modify the Protocraft trucks to enlarge the hole to go around this pivot.
Since the Protocraft truck was almost as expensive as the car, I set a requirement to not modify the trucks during my conversion since I wanted the option to sell the trucks separately if my interests ever changed & I also wanted the option to reuse the trucks on another 100-ton car.
I did notice that Protocraft has run out of the100-ton 2-rail roller bearing trucks when I was thinking about buying more of these Husky cars a few months ago. Since the trucks were unavailable, I did not buy any more Husky cars.
But these trucks are the smoothest trucks I have ever experienced. The car rolls very smoothly. I didn’t even realize I had a slight sag in the middle of my computer table until my Husky cars with Protocraft trucks started rolling unassisted on a section of track.
These are just my opinion,
Thanks,
Naveen Rajan