Just about any of the green NYC and Pullman Heavyweights. Lionel, MTH, and K-Line have made nice 18" cars both with and without interiors. 3rd Rail has made 21" cars. All of the cars made after about 2004 have both interiors and figures. I have them all and mix and match them. K-Lines couple a little closer, then MTH and Lionel's have the widest gap. The Hudsons pulled most all the passenger trains in the '30s. The 20th Century was a mix of Pullman and NYC. Others were all NYC.
Pete