Complex sentence: From 1997 for several years there were museum steam trips on Wangerooge every summer hauled by a "Franzburg" locomotive from the DEV which was brought across from the mainland for that purpose.
Split into simpler sentences: From 1997 for several years there were museum steam trips on Wangerooge every summer. A "Franzburg" locomotive from the DEV was brought to the island from the mainland for that purpose.