Many freight cars built in the 1920s were equipped with Dalman trucks. The Dalman 2 Level truck design used additional springs to give a smoother ride. Railroads using this version included C&O, CGW, ITC, L&N, MILW, M-K-T, NC&StL, PM, TC and many Texaco 10,000-gallon tank cars.
Below is a link for the data sheet about this truck.
TMW-101 / TMW-201 Data Sheet