The fuel efficiency of the DMUs seems like a great economical way to move people around but I don’t read about this equipment anymore. Getting 2 miles to a gallon of fuel is very impressive seems like a good start to getting the most out of an ever increasing expensive fuel. What are the drawbacks to this equipment?
Well, I’m not an expert, but here’s a few things to throw out onto the table :
There will be more engines in these trains. That’s a given, and more engines usually mean more mainteance, but if the engines are smaller, and use non-railroad parts, they may be cheaper to maintain.
If a car breaks down, unless a spare part is ready (such as a truck or transmission assembly) the whole car is out of service. With a normal train, a new passenger car would just be substituted. (The DMUs probably cost more per car.)
That’s really all I can think of.
Someone else will probably be able to elaborate better.
Just been looking at CR. Looks to me they’re making some progress.
Don’t quote me but…I seem to remember that MU cars (electric) fall/fell under more stringent inspection schedules because they were classified akin to locomotives, whereas cars were, well, just cars. If I rememebred THAT part right, I would think DMU’s would have the same thing, too. So, more maintenance and more inspections can add up to more downtime.
You are correct. Any mu, diesel, diesel electric, electric, multi-mode, battery-flywheel, requires 90 day inspections, if I remember correctly, whereas a non-powered coach gets them yearly, if I remember.
Still, the RDC was very popular, and Colorado Railcar is selling to some commuter authorities.
Colorado Railcars is promoting the pulling of trailers – a big no-no with RDC’s – apparently the CR equipment is heavier duty. If you can go 1:2 or even 1:1 on DMU to trailer, that should be some cost saving on the 90-day inspections and on maintaining a powered car.
As to the 2 miles per gallon, that is a number they just throw out – one would need to see what the actual fuel usage is in service depending on speed, number of stops, etc. Also CR website has cost savings that are (of course!) favorable to loco-pulled trains for short consists.
To some extent, the Diesel-electric locomotive is derivative of equipment developed for marine applications and especially Diesel submarines. The DMU is derivative of equipment developed for heavy-duty over-the-road trucks and buses. The CR DMU power train should be quite proven, but then railroad applications may put stress on equipment not encountered in automotive use – mainly much higher ton/HP ratios plus a different shock environment.
I was looking at the website selling the CR DMU’s-I have to admit I’m kind of impressed. 188 passengers, ADA acessible restrooms & room for wheelchairs in a self propelled unit that can pull a trailer or two! That’s a lot of stuff in one piece of equipment! I’m still used to gallery bilevels being hi capacity (about 170 people and too cramped for any hope of ADA compliance)/hi tech solution for high density routes.
Unpowered trailers seat an even 200!
A couple of things. The 188 passenger CR DMU is a full double-deck unit that tops out at 20’ 11" above the rails. It also has the seats under pretty short pitch.
The newer gallery bilevels are also ADA compliant – they have ramps to get people past the entry stairs, they have an ADA bathroom in them. No, the entire car is not ADA accessible – no ramp to get up in the gallery.
A lot of how the gallery car gets a lot of seating is what I call the “peanut gallery” – the long row of sideways-facing seats that packs in the overflow crowd. At least the CR bi-level seats everyone on conventional 2+2 seats.
The CR bilevel is an interesting approach to low weight per seat and hence energy efficiency. The FRA buff standards require heavyweight cars, but the bi-level only needs to carry the same buff force as a single-level – if you think of a car stood up on end as a pylon, making the pylon twice as fat can make it easier to carry the load.
As to seating density, you get what you pay for. People complain “a bus is too crampled”, “a plane, fugetaboutit, way too cramped”, but one way to get energy and cost efficiency is to stuff in seats, certainly what the airlines have done. CR’s pitch with the DMU is mainly towards commuter agencies, and there is an acceptance of higher-density seating there compared with long-distance.
The DMU’s would probably be a better investment in operations like the upcoming Albuquerque service, branches like the Princeton and New Canaan shuttles or rush-hour only operations like Metra’s Heritage (ex-GM&O/Alton) line and NJ Transit’s Pascack Valley line.
I personally have always been of the opinion that conventional loco service is more practical than MU passenger service (mainly for the same reasons as mentioned above), but they have been the pet child of the German DB Railway since the 1950’s.
The advantages are lower maintenence costs (surprising, but coming as a result of utilizing diesel components designed by the automotive industry), less tonnage per axle (lowering rail maintenence costs), lower personell costs (just one operator), and a lower floor level, enabling level passenger access from the platform. The relatively low purchase price (compared to conventional loco and passenger cars) has also enabled a plethora of new, private railways to get a foot in the door for providing service throughout Germany.
DMUs are considered the savior of passenger service on branch lines in Germany, the Siemens Desiro being the most common model.
Austin light rail has chosen the Siemens DMUs for their new service. I think finance options were a big deciding factor.
dd