I don't know how hard the Lionel passenger cars or their trucks will be to convert to 2-Rail, or if it will be even worth it. Lionel posted a "Virtual Train Show" where they showed samples of the upcoming Reading passenger cars. We don't know how close this will be to the final product. It looks like the vertical springs are missing, maybe they will show up on the final model. https://youtu.be/_0lCDuq-LEU?t=2038
I also grabbed a picture of trucks from a Jersey Central coach for comparison.