[ardecila]

I’ve heard that DMUs come with a extraordinarily high O&M cost per passenger. It makes sense, you have a whole motor and fuel system inside every car to be fueled and maintained. They really only make sense for regional lines with relatively low demand and closely spaced stops, because the added expense of maintaining 2-car or 3-car consists is outweighed by fuel savings from the greater efficiency (more motors mean more drive wheels, so less loss of energy to heat and friction).

I’m not sure Metra has any operations that make sense for DMUs, the rush-hour demand for service is too high on virtually all the lines. DMUs might work for off-peak or weekend service on some lines, but it’s not worth the expense and headache of maintaining two separate fleets.

If Metra ever got serious about providing frequent regional service, DMUs might work in lieu of electrification, but they can’t scale up if the service proves popular. Really the best candidate for DMU service is not Metra service but the proposed Amtrak services to Rockford, Quad Cities, etc. But then you’ve either gotta use absurdly heavy DMUs that comply with FRA regulations, or somehow get a waiver covering hundreds of miles of active freight lines. Even other US cities with DMU operations are only using them on suburb-to-suburb operations with limited demand and either dedicated passenger tracks or a clear time separation for freight.