Queenposts with a slotted top are the most common model style. One "trick" I've read of over the years, from multiple authors, is to use a single piece of fishing line for the rods. Thread it through holes near the bolster to fit all of the queenposts, leaving the line off the post on one pair. After the line is tied tight inside the car, left that one onto the posts, ensuring that the entire line is tight.
It doesn't work too well for flatcars or gons, because there's no "inside" to hide the knot. On my Nn3, I ran the line THROUGH the bolsters, between the coupler and the bolster for the center sill, and tied both ends outside one end sill, before tensioning it. A large nut-bolt-washer and a small knot don't look that different, at normal viewing distances, in N scale.
