HO Gauge Jouef TGV : Repair Request

I was sent this HO Gauge Jouef TGV by Trevor on behalf of his son Chris as it wasn't running at all well. Merch - https://oobillmerch.creator-spring.com Support - https://ko-fi.com/oobill73561 FAQ - https://ko-fi.com/post/FAQ-C0C6E0UO4