Atlas entered the market for ready-to-run HO scale diesel locomotives in 1975, importing models produced in Austria by Roco. Six models of various EMD diesels made up the base of this initial offering through the 1980s. Complete train sets were first offered by Atlas in the 1970s, using the Roco-produced diesels and freight cars supplied by Athearn. Atlas later forged a partnership with Japanese manufacturer Kato Precision Railroad Models to release an Alco RS-3 in 1984 that raised standards in the hobby for fine scale fidelity.