Sunday, July 31, 2016

Diesel Multiple Units in 21st Century America


US public transport officials working with finite resources to build and operate new fixed guideway transit services grow more and more creative every year, finding ways to offer new and expanded services with fixed or declining resources. One creative approach to the development of new urban passenger rail services has been to operate new passenger rail services on tracks shared with light density freight services. Most services have used conventional commuter rail passenger rolling-stock for these services, but in some circumstances this relatively heavy equipment has been inappropriate, forcing officials to look into sharing freight tracks with lighter shorter trains. Some of these trains have been conventional electric light rail cars, but since the turn of the 21st century, five new services have opened using self-powered diesel rail cars (commonly called DMUs) to offer new travel options in Texas, California, New Jersey and Oregon. The Federal Transit Administration (FTA) has termed these new shared track services “Hybrid Rail.”


David Nelson, Tara Blakey and David Nelson recently reviewed the circumstances and conditions that gave rise to the development of these hybrid DMU systems. They used federally reported data to conduct a comparative survey and evaluation of these services compared with electric light rail and conventional commuter rail services. The analysis finds that the new DMU systems tend to function in a new service stratum between commuter and light rail, serving markets that neither traditional mode is well suited to address

Their analysis finds that the new DMU systems tend to function in a new service stratum between commuter rail and light rail serving markets that neither traditional mode is well suited to address.
  • Service Density – At 5,000 to 10,000 annual train miles per directional route mile, the new hybrid DMU systems clearly offer greater service density than similarly scaled commuter railroads but in no case do they offer the higher service densities associated with US light rail services. The hybrid systems generally offer more travel opportunities than commuter rail services but fewer scheduled trains than light rail services. 
  • Service Velocity – At 20 to 25 train miles per train hour, the hybrid systems tend offer a higher service velocity than light rail but slower one than commuter rail.
  • Station Spacing – With 1.5 to 4 one-way route miles between stations, the hybrid DMU systems have a greater average station spacing than nearly all light rail lines and less than all smaller commuter railroads.
  • Average Train Length – The typical hybrid DMU train is one or two cars. This is typical of most smaller light rail services and less than all US commuter railroads.
  • Passenger Density – The hybrid DMU rail services tend to attract 150,000 to 650,000 annual passenger miles per directional route mile. This is consistent with smaller commuter railroads but less than all but a few light rail services. As these new services mature it is certainly hoped that their passenger densities will rise with the development of the environs surrounding their stations.
  • Average Passenger Trip Length - The hybrid DMU systems service typical trip lengths in range of 10 to 15 miles per passenger. Light rail systems all have shorter average length. Commuter rail system average trip lengths range between 15 and 45 miles
  • Average Train Load - The ratio of passenger miles to train miles for the typical DMU service is typical 50 passenger miles per train mile, consistent light rail services. Commuter rail average train loads typically tend to be much higher.
  • Transport Operations Costs per Train Mile – The emerging hybrid DMU services exhibit train operations costs in the range of $10 to $20 per train mile consistent with most light rail services with similar train lengths and crewing regimes. 
  • Mechanical Maintenance Costs per Vehicle Mile - Reported unit costs for the RiverLINE, Sprinter and Cap Metro are approximately $4.00 per vehicle mile somewhat above the median for other commuter rail and light rail services. This may be partially due to their small fleet sizes. 
  • Total O&M Costs per Train Mile - The new DMU services with short trains range between $30 and $60 per train mile. Most light rail services fall in the range of $20 to $40 per train mile. Most US commuter railroads range between $50 and $200 per train mile. The larger and more mature hybrid DMU systems with more extensive service tend to have lower average costs.

Thursday, December 24, 2015

Revised Agenda for 2016 Annual Meeting



2016 Annual Meeting Agenda
AP070(1) Self-Powered Rail Car Technologies Subcommittee
Joint Subcommittee of AP070 and AR020

Monday, January 11, 2016 | 8:00 AM- 9:45 AM  
Marriott Marquis, Pentagon (M4), Washington, DC

David O. Nelson, Chairman | Secretary, Vacant


1.   Non-Minutes from Annual Meeting January 12, 2015
a.   The subcommittee desperately needs a secretary.  
About 8 hours of work per year. 

2.   Subcommittee Management
a.   Chairperson Succession
b.   Secretary

3.   Discussion Topics
a.   Recent Developments involving Compliant Cars
               Click here for Sonoma Marin Presentation by Ted Rosenbaum of LTK
b.   Recent Developments involving European Design Cars
c.    Plans for other systems?

4.   Research Plan and Agenda
a.   Empirical Analysis of DMU Economics - 2013 NTD:  YR (Hybrid Rail Mode)  Five systems

b.   Twenty Years After: Progress with North American DMUs

c.    Has FRA alternative compliance has affected fleet decisions of North American transit providers?

d.   Consist Flexibility: Combining and Splitting Trains in Revenue Service
     Presentation by Andrew Jennings


Sunday, January 4, 2015

Announcing the 2015 Annual Meeting!!!




2015 Annual Meeting Agenda
AP070(1) Self-Powered Rail Car Technologies Subcommittee
Joint Subcommittee of AP070 and AR020
Monday, January 12, 2015 | 10:15AM - 12:00PM  
Marriott Marquis, Mint (M4), Washington, DC
David O. Nelson, Chairman | Secretary, Vacant



a.   The subcommittee desperately needs a secretary.  About 8 hours of work per year. 

2.   Subcommittee Management
a.   Chairperson Succession
b.   Secretary

3.   Discussion Topics
a.   Recent Developments involving Compliant Cars

b.   Recent Developments involving European Design Cars

c.    Plans for other systems?

4.   Research Plan and Agenda
a.   Empirical analysis of DMU Economics

b.   How Alternative Compliance has affected fleet decisions of North American transit providers?


c.    Other suggestions




Thursday, January 16, 2014

Draft Minutes from the 2014 Annual Meeting




Please Click Here to review minutes from the 2014 Meeting of the Self Power Rail Car Technologies Subcommittee.  


Comments or questions can be directed to david.nelson@jacobs.com

Minutes from the 2013 Annual Meeting


Please click here for minutes from the 2013 Annual Meeting of the Self Powered Rail Car Committee