The British Rail Class 158 Express Sprinter is a diesel multiple-unit (or DMU), built specifically for British Rail between 1989 and 1992 by BREL at its Derby Works. They were built to replace many locomotive-hauled passenger trains, and allowed cascading of existing Sprinter units to replace elderly 'heritage' DMUs. The Class 159 DMUs are almost identical to the Class 158s, having been converted from Class 158 to Class 159 in two batches. ScotRail was the first part of British Rail to introduce the Class 158s to public service in September 1990, long after the planned date. These were employed on Glasgow Queen Street to Edinburgh Waverley services, as well as services to Aberdeen and Inverness.