by TomNelligan
DMUs have been discussed quite a bit on the Amtrak forum (in connection with an Amtrak proposal to use them on the Vermonter route) and the subject comes up on other transit forums here as well.
An issue that exists on the Fairmont line is the need for equipment that meets all FRA structural requirements for mainline railroad operation. New Jersey's River Line is extempt from this because passenger and freight operation are time-separated (CSX uses the line only in the middle of the night). I believe that Colorado Railcar is the only company currently offering DMU equipment that meets FRA codes, and customers haven't exactly been beating down their doors.
The MBTA, like almost all other US and Canadian transit agencies, has opted for locomotive-hauled push-pull equipment on non-electrified lines. (Two exceptions are the relatively small-scale systems in Dallas/Ft. Worth and Syracuse that use rebuilt RDCs.) It has been frequently reported that between the FRA structural requirement and the need for increased inspection and maintenance on self-propelled cars versus unpowered coaches, most systems have to date considered DMUs to be cost-inefficient. Certainly the disasterous mechanical failure rate of Budd's SPVs in the 1980s didn't help either. Again, the River Line is an exception because it has been able to use transit-type cars thanks to the time separation. Ottawa also has a small commuter operation that uses Bombardier DMUs, but obviously FRA rules don't apply in Canada and I believe the Ottawa system is time-separated from freight operations anyway.
An issue that exists on the Fairmont line is the need for equipment that meets all FRA structural requirements for mainline railroad operation. New Jersey's River Line is extempt from this because passenger and freight operation are time-separated (CSX uses the line only in the middle of the night). I believe that Colorado Railcar is the only company currently offering DMU equipment that meets FRA codes, and customers haven't exactly been beating down their doors.
The MBTA, like almost all other US and Canadian transit agencies, has opted for locomotive-hauled push-pull equipment on non-electrified lines. (Two exceptions are the relatively small-scale systems in Dallas/Ft. Worth and Syracuse that use rebuilt RDCs.) It has been frequently reported that between the FRA structural requirement and the need for increased inspection and maintenance on self-propelled cars versus unpowered coaches, most systems have to date considered DMUs to be cost-inefficient. Certainly the disasterous mechanical failure rate of Budd's SPVs in the 1980s didn't help either. Again, the River Line is an exception because it has been able to use transit-type cars thanks to the time separation. Ottawa also has a small commuter operation that uses Bombardier DMUs, but obviously FRA rules don't apply in Canada and I believe the Ottawa system is time-separated from freight operations anyway.