MTH makes a variety of 2 rail trucks for all their rolling stock. (Passenger, freight, caboose, roller bearing, plan bearing, 70 ton, 100 ton)
https://mthtrains.com/prod-sea...lassification%3A7036
They screw right in to the existing bolster without any modifications, and they have the added advantage of lowering the car to the correct height. You may still be able to get these from a variety of sources