This is Atlas 50001705 N 70-Ton Hart Ballast Car, RI #101024. 70-ton Hart ballast car, Rock Island #101024. Built by ACF from 1940-1953, the 70-Ton Hart Ballast Cars were formally known as Hart Selective Service Ballast Cars, due to the use of specially-designed doors which allowed the lading to be discharged one of three ways: to the center of the rails, to the center and sides of the rails, or to the side of the rails only. Its key features are: Die cast chassis 70-ton friction bearing trucks Accumate offset shank coupler Fully detailed interior, including cross-bracing and side stiffeners Accurate painting and printing Manufacturer: Atlas. Model Number: 50001705. Scale/Era: N Scale. Model Type: Freight Cars.