Four locomotives (numbered E31 to E34) were built at Seibu's Tokorozawa factory between 1986 and 1987 to replace ageing first-generation electric locomotives on freight services and track maintenance train duties.

They were normally used in pairs by Seibu for top-and-tailing permanent way maintenance trains and to haul newly delivered rolling stock.

[3] Initially they were used only for depot shunting duties, but from 2017 they underwent overhaul in preparation for use as helper locomotives on steam-hauled trains,[4] with the first locomotive treated, E34, scheduled to enter revenue service on 15 October 2017.

Locomotive E31 remains preserved at Seibu's Yokoze Depot.

西武鉄道 電気機関車小史２ [Short History of Seibu Electric Locomotives].