Shades of the Brill Maximum-traction truck from 1911, notorious for, uh, wandering… Brill used an off-center bolster to distribute more of the car’s weight onto the powered axle. On an RDC, the only additional weight on the inner axle was the Spicer drive and about half of the weight of the cardan shaft.
No, although it is certainly portable.
I usually do use the abbreviation “.pdf” to make it clear that it’s something fairly large that’s going to be downloaded or inline-opened when I’m actually posting a link to one…
(Yes, I know this was ‘in fun’…)
It isn’t quite that simple. The portion of the horsepower that is needed to overcome air resistance goes up by the cube of speed. So if you double your speed you need 8 times the horsepower to overcome the air resistance. That is only part of the horsepower requirement for speed but it is certainly not linear.
Looking across the other ocean, a sizeable percentage of Japanese juice burners had six powered axles. The earliest box cabs ran 1-Co+Co-1 for freight, 2-Co+Co-2 for passenger service. Then there was the real oddity, Class EF55, which was a 2-Co+Co-1 with a streamlined cab at the four wheel truck end and a conventional box cab at the two-wheel truck end. Class EF58, 2-Co+Co-2, the last of the articulated-frame electrics, has a box body with nicely shaped semistreamlined ends. One, EF5861, remains available to pull the Imperial Train on lines which retain 1500VDC catenary.
Post-WWII the Bo-Bo-Bo design became popular, and continues so to the present. There were only two Co-Co classes, massively heavy machines designed to climb (and descend, as brake helpers) the 6.8% Usui grade at very modest speed. After the Usui grade was taken out of service they were tested elsewhere, but were unsafe at normal freight speed.
There were a number of classes of four-axle power in Bo+Bo, 1-Bo+Bo-1, Bo-Bo and, my very favorite, the ED72 class Bo-1-Bo. Yup, one laterally-moving unpowered axle amidships, needed to support the weight of a train heat boiler and its water tanks.
Note that all of these were/are 3’6" gauge, so even the ‘high speed’ locos aren’t very fast by North American or European standards. There are good reasons why the Shinkansen network is standard gauge.
Chuck
Far from me to criticize someone who not only knows this subject better than I do, but was there – but my understanding is that the ED72 class would be Bo-2-Bo in your system, with the 2 being axles (as in the German system) rather than wheels (as in Whyte coding):
Now it may well be that this class was originally built with a single axle in the middle; the early NYC third-rail locomotives had Bissel trucks, and the very talented man who designed those locomotives resigned when ‘higher-ups’ started shoehorning two-axle trucks into them without consulting him first…
If so, please let me see a picture or drawing that shows the underframe arrangement.
My apologies about the misidentification of the JNR Bo-1-Bo class. I shot from the hip [my key reference book is temporarily (I hope) AWOL] and scored a clean hit on my toe. The ED73 (and the later ED76-) is Bo-2-Bo.
Checking locos used on private electric railways, all but a handful were Bo-Bo or Bo+Bo. The oddballs, all Bo-Bo-Bo, were all withdrawn from service when their owners discontinued freight service.
Chuck
There are six axle electrics, like the Bombardier IORE (these run normally as a pair), and locomotives like the NEWAG Dragon. In Germany, there are still many BR151 and BR155 hauling freight, like this: https://youtu.be/XfVxkiYxcgw And that does not includes the beasts of Gotthard: https://en.wikipedia.org/wiki/SBB-CFF-FFS_Re_620 Or the classic BR103 passenger electrics https://en.wikipedia.org/wiki/DB_Class_103 N. F
Having checked Japanese Wikipedia…
ED62, a rebuild of ED61…
So DC and not AC.
https://ja.wikipedia.org/wiki/ファイル:ED6214b.jpg
(I wonder if that will work…)
M636C
It does for me … nicely. Oddly enough, typing “Bo-1-Bo” into Google gives one hit on Wikipedia that mentions the ED62, and there are a number of English-language pages with information. The class is apparently covered in Inouye’s JNR locomotive encyclopedia, if anyone here owns a copy or has access to one.
The conversion was done fairly recently (middle to late '70s) and was successful enough that the last example survived into the new millennium. Three, perhaps four, have been preserved.
Now can someone describe the details of the single-axle support? The necessary load reduction wasn’t much (from 15 to 13 tons axle load) and it certainly seems easy to get a single axle in, which at the center point between the truck pivots is going to track well even on spiral-transition curves.
The key is the reduction to a 13 ton axle load - the maximum for a lot of rather lightly-built lines which received 1500VDC catenary in the immediate postwar period. There were several steam loco rebuilds (from 2-8-2 to 2-8-4) done for the same reason (and operated earlier on the same lines.)
I should have realized that the place to look was in 1500VDC-land. That’s (part of) what I model in 1:80 scale.
Chuck (Modeling Central Japan in September, 1964)
The ICE 2s are a half set version of the ICE 1. The ICE 3 and the new ICE 4 are Distributed Traction trainsets.
Hi,
it all has to do with what the railroads require, and simple economics. I can only talk about the German railways, it was Siemens that started the development of AC traction and now makes engines with about 8600 hp that weigh about 90 ton. A far cry from our ES44ac’s or SD70ACe’s.
In Germany you need HP to move freight trains at high speeds. From my knowledge the heaviest Unit train in Germany is 5000 Tonnes. For that two AC’s are sufficient, this train was pulled for the longest time with Two E151 Electric engines that weighed 120 tonnes and had 8000 hp each, but they were DC and could not put down their power as well as the AC’s that even though being lighter can fulfill the task. To get the train rolling faster they use a third electric engine similar to the ones pulling up front to push from the rear. Totally unheard of in North America, but required in Germany to not impede the passenger trains.
Here in North America, there are no Government subsidies like in Europe and Freight rules the Rails. It is therefore more cost effective to have a heavier diesel engine that can produce the max amount of torque-hence the weight and extra driven axles-to move the longest heaviest possible train at a slower pace over the rails. If the train is to move faster then just hook up another diesel and off you go.
Also the SD70mac and SD90mac actually used Siemens technology in their locomotives and we know how that worked out with the 6000 hp engines.
Hope this explains things a little.
Frank