When you spend as much time as I have lately at old truck forums, you inevitably run into some new and unusual things, like this Freightliner Power Dolly, created to provide additional thrust on a second semi trailer when two or three trailers were a bit much for the tractor in the mountains in Oregon.
Here’s a closer look at it. It’s got a 130 hp Cummins V6 diesel pushing through a torque converter and then directly to the axle differential. That’s to eliminate a clutch and gears, for obvious reasons. The controls for it in the cab had only three positions: 1) full throttle for starting off, 2) 80% throttle for running when power from the dolly was desired, and 3) idle. Applying the brake automatically kicks it into idle. And then apparently it shuts off, presumably to start up again when needed.
Here’s another look at one installed.
And with its fairings in place.
As per a comment by a knowledgeable poster:
The Power Dolly was created at the request of Bend Portland Truck Lines who wanted to begin hauling Triples between Bend and Portland but didn’t have the traction over the passes. Testing was done not only by Bend Portland, but also CF and Garrett.
Here’s a picture of one of the CF test unit heading up one of the snowy Oregon passes. Looks familiar.
From the same commenter:
The information from the testing was that the combination was more stable in the snow since the tractor drive axles were not operating so near their slip limits, and with the power dolly never approached its slip limits. Despite this, I have found no information that Freightliner ever sold any commercially.
I’ve read more recently about some ideas of having trailers with batteries and their own EV drive trains, but there’s some issues with that, as a lot of capital in the batteries and motors would often be not in use, as trailers are not infrequently tied up at various locations.
It’s impressive looking at the design solutions people found when engines were insufficiently powerful and there weren’t computers to manage the power that was available. It’s one thing to run slave engines in truck dollies. It’s quite another to figure out how to make them useful and safe with only mechanical controls that had to be routed through trailer couplings.
Boy did this pull some long ago memories out of the old brain. That is probably a Cummins VAL V6 engine. Cummins made a V6 and V8 engine family, VAL-V6 and VALE-V8.
Climbing mountain grades with one drive axle can be a problem. IIRC UPS experimented with some 4×4 tractors.
Freightliner made 4×4 COEs called the Mountaineer. We covered them here:
https://www.curbsideclassic.com/blog/car-carriers/car-carrier-of-the-day-4wd-freightliner-yes-4wd-ready-to-tackle-the-rockies/
We ran the Mack 4wheel drive tractors here in Montana for UPS for nearly 20 years.
I recall seeing single axle trucks in Ohio having issues I can only imagine how that could have helped everywhere and how it could be a help these days in many ways.
I heard those small Cummins V-6’s and V-8’s were designed in England primarily for Europe but Ford used them here quite a bit in the 60’s. The V-8 eventually evolved into the 555 and later VT-225, dissappearing sometime in the 80’s.
As for the powered dolly, it has ‘jacknife’ written all over it!
Hey Bob you might want to research power trailers, they are still big here in Australia in mining
From a economic stand point, railroads can haul frieght much more efficient. It’s a sad state of affairs that we as a country let this deteriorate. Union Pacific always had the locomotives to move the tonnage over the mountains for years on end. But lot of this was lost to the trucking industry, sadly, now, more than ever with the emissions, driver shortage, and hours of service rules. I don’t think we will ever be the same as years ago, the politicians, and others killed this industry……
I don’t think we will ever be the same as years ago, the politicians, and others killed this industry……
This “dead” industry is very much alive, and has actually struggled in recent years to keep up with the demand. UP and BNSF are roaring out here in the west, and making record profits.
Part of this is due to the chronic shortage of truck drivers. At the moment, there’s over 8,000 unfilled truck driving jobs, and that’s getting worse by the day. So shippers use railroads whenever it’s feasible.
BTW, the majority of trucking is not long haul, but short and medium haul, which the railroads cannot do. All those endless containers from China and other places that arrive in West Coast ports make their way inland on trains, not trucks.
Blaming government for everything is just plain silly and uninformed.
Railway stocks have done very well in the past few years. The five year on my CPR stock is 141%.
I bought CNR at $11.00 in 2004. Today it’s at $154.00.
The problem in the Great White North is now capacity.
I fully understand the truck driver shortage. In the “good old days” of the 1950s and 1960s, freight rates were set by government, at least here in Canada. Most truckers were in unions and therefore made decent wages. We are now in an anti-union culture in much of North America and wages have suffered. Again, that 1950s nostalgia was partly due to the success of unions.
Now it is simply not worth the effort one has to put into it.
So, yes, my t-shirt is cheaper but now I can’t get it transported to the store.
On the other hand, a robust independent owner operator situation also encourages larger employers to pay more in wages. After all, if a good employee can strike out on his own or with a small team, then the larger employer has to increase benefits. Unfortunately, this type of business becomes more difficult with increased regulations. Trucking has added layers and layers of regulation to the point where it’s no longer attractive, because it is extremely difficult to operate on a profit, small scale.
To say the government (by the will of the people) hasn’t had a hand in this is myopic, I believe.
The US ships three times more freight by rail than Europe. Half of Europe’s freight goes by truck vs. 40% in the US. The rail industry in the US is booming and profitable. Europe, due to geography, ships much more freight than the US by water while the US ships much more than Europe by pipeline.
This doesn’t surprise me. Driving along any Western interstate that goes close to a major rail line one sees a phenomenal number of hugely long trains, many hauling miles of containers stacked double-high that are clearly coming from West Coast ports. Conversely, more and more trucks seem to be hauling van trailers presumably for regional grocery chains or Walmart, and of course Amazon, USPS, UPS and FedEx.
As others have noted rail freight is doing well. What they have let go is the final mile. In the area where the non-profit I’m involved with has their warehouse there are dozens of spurs serving many of the warehouses through the valley. One of the reasons that are was initially developed as industrial/warehouse was the rail lines that ran through the area. Now just a few of the spurs ever seen any traffic, most are abandoned with the rails cut at either side of the road, or like the one that “serves” our warehouse with more rotten ties than good.
Meanwhile the trains rumble along the mainline at such frequency that they keep adding overpasses to keep the rubber tired traffic moving through the valley.
It isn’t a big surprise they dropped most of the final mile service, yes rail is more fuel efficient, when up and moving. However, it just costs too much having those expensive locomotives and crews spending all that time dropping off and hooking up.
Technology killed train transportation and there’s no driver shortage get your facts straight. The feds issue over 3 million new CDLs each year. The truth is driver retention mainly pay$. Then everything you do as a driver has huge criminal implications. You can get a felony charge for log book violations. Or 110 years in prison like the driver in Colorado was just sentenced to. Luckily the governor commuted it to 10 years. Flipping burgers at McDonald’s looks way better.
All new to me, I had never heard of these before. An interesting concept and solution.
Regarding EV drive trains in the trucking business, the latest set-up I’ve just read about is the Smesh-E-Axle for heavy-duty BEV trucks and tractors. Everything integrated in the rear axle.
https://smesh-e-axle.com/en/
That is very interesting, it certainly is refreshing to see a focus on ultimate efficiency with the dual motor multi-speed transmission set up.
Interesting idea but I agree with Bob B. as to the jacknife potential. We had a pair of front engine Bluebird buses at work powered by the Cummins 504 V8 motors. PT pump fuel system like the 855s. The British considered it a challenge to cast Made in Great Britain on everything no matter how small the part. Sometimes abbreviated to G.B. Pretty good oil leakers like most mechanical things British of the era, the mechanical noise was incredible. At least they didn’t smoke like the Cats. Biggest problem that if it was below 60F they HAD to have a sniff of ether to start.
When building interstate 80 over Donner Pass, one guy rigged up a powered trailer axle to help power the loads of bridge beams up the mountain. Also near Pittsburgh PA a company has produced a powered trailer axle using electric as a fuel source. Pittsburgh Power also developed a electric powered drive axle but they sold it to another company.
I smiled while reading this one, Paul. Commenting on your very recent writeup of PIE and the (unsuccessful) GMC engine, I posted a couple pages of a 1953 SAE Transactions article (from Caterpillar) delivered to its west coast chapter, “What’s Ahead in Commercial Vehicle Powerplants.”
What’s below is from the discussion–and the Timken-Detroit guy suggests using a part time assisting engine for the western grades. Cool!
These piggy back engines are used in Australia on some road train operations, why the hell would you be using single screw tractor units in mountain country just asking for traction problems
Really? They never have to climb anything properly called a steep slope, though perhaps it’s for endless miles of boggy bog when the rains do happen?
There’s some parallel here with the “60-foot” articulated City Buses that hinge in the middle to go around corners.
Early buses had the driven wheels ahead of the “hinge” in the middle. (The middle axle was driven.) This amounted to the front-half of the vehicle pulling the rear half, not unlike a tractor/trailer combo.
Later buses had rear engine, rear-axle drive. Now the “trailer” was pushing the front half. This is wildly unstable, so the hinge gets big hydraulic rams to stabilize the joint. That would be totally lacking in a powered semi-trailer configuration. One difference is that the powered semi-trailer probably isn’t actually pushing the tractor, merely reducing the “pull” on the hinge.
It actually seems a rather good idea for mountainous country, especially in today’s era when electronics could control so much of the operation, but I harbor a suspicion that the weight/fuel-use maths don’t work out.
Literally only a suspicion, but I always just assume that any freight-related idea has always been taken apart down to its last quarter-cent by clever actuaries and logistics smarties, given the margins and sheer volumes.