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Is the constraint on the loading gauge restriction height or width? A roadrailer would be designed around the ruling loading gauge in effect:

I've helped unload one of these, when I was working in the warehouse.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

by BruceMcF (agila61 at netscape dot net) on Mon Jul 16th, 2012 at 01:16:02 PM EST
[ Parent ]
Height. British loading gauge would only allow containers to be carried, not lorries

keep to the Fen Causeway
by Helen (lareinagal at yahoo dot co dot uk) on Mon Jul 16th, 2012 at 01:48:22 PM EST
[ Parent ]
In effect, both height and width are a problem: traditional European loading gauges have a more curved roof section than American ones, and the key for any kind of intermodal is corner height. Making rail lines suitable for high-cube containers (height 9'6" instead of 8') resp. 4-metre standard height European trucks is a challenge in continental Europe, too (for example, in long tunnels in Switzerland, the solution was to lower the trackbed and replace the catenary with roof third rail). Check extended UIC profiles on page 22 of this document, which also shows the British profiles on later pages.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Mon Jul 16th, 2012 at 02:34:26 PM EST
[ Parent ]
I wanted to comment this, too.

On the loading gauge aspect:

  • The most advanced US roadrailer system (it's suitable for high speeds, at 70 mph actually higher speeds than most European low-floor solutions) is the RailRunner's Terminal Anywhere. They don't actually give the figure anywhere, but it appears that the wheeled end of their standard semi-trailers is lifted 9' (contact surfaces at c. 40' resp 49' above rail), that's about 230 mm.
  • Modalohr loading height is 207 mm.
  • Another new rotating chassis solution from Europe, Megaswing, has a loading height of 270 mm.
  • Classic RoLa is between 310 and 480 mm (the higher end of the range is the minimum height possible above the bogies, but many car types have lowered paths between the bogies).

The pros and cons of these systems also include weight:
  • Terminal Anywhere leads by leaps and bounds in train tare weight on unit length: 0.73-0.83 t/m, of which the bogie contributes 0.39-0.5 t/m. From what I can find, they even achieved this without substantial increase in semi-trailer tare weight, in spite of the need for specialised chassis with higher structural strength.
  • Necessitated by the double chassis (static and rotating parts), Modalohr cars are heavy: 1.27 t/m.
  • Megaswing cars don't have a double chassis, but have parts that need to be specially strong too: hence a tare weight by unit length of 1.22 t/m (single version) resp. 1.12 t/m (twin version).
  • Classic RoLa cars are in the range 0.85-1.1 t/m (newer ones tend to be lighter).


*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Tue Jul 17th, 2012 at 02:55:59 PM EST
[ Parent ]
The point I was raising regarding loading gauge with the Roadrailers was piggyback loading gauge, not container loading gauge.

Given the way that the Roadrailers carry their road tires a short distance above the rail, there is no way any piggyback with the tires sitting on a rail car can fit inside the same railway loading gauge with the same interior cargo height as a RoadRailer. And a Roadrailer would be designed for the ruling loading gauge of the network it runs on. Any piggyback trailer with the same capacity per length, will be higher than an equivalent Roadrailer, or conversely any Roadrailer with the same external height above the rail as an equivalent piggyback will have a greater capacity per length.

The Railrunner is not a normal Roadrailer, its a chassis for a standard container that converts it into a road railer. The bogie is a separable unit that replaces the semi truck with a rail truck, but that is how the newest Roadrailers do it as well ~ the original Roadrailers of the 1950's had bogies that lifted up out of the way when on the road and then were dropped down and locked into place to carry the trailer on the tracks, but a separate bogie is the more effective solution ~ if you normally send the truck out and then it returns to the same railhead, carrying the bogie as deadweight there and back is not the most effective solution. Also, that allows a single rail coupling bogie on either end of a string and a specialized inter-trailer bogie in between the trailers in the string.

The Railrunner would be a more comfortable fit for the CargoSprinter type of system, though, since the control pass through between lead motor unit and trailing motor units could be built into the chassis and the connection tested in-cab when the consist is marshalled.

The highest profile Roadrailer service in the US is the Triple Crown, established in the 1980's by the Norfolk Southern and since the 90's joined by BNSF to include service between Kansas and Texas.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

by BruceMcF (agila61 at netscape dot net) on Tue Jul 17th, 2012 at 05:52:40 PM EST
[ Parent ]
The point I was raising regarding loading gauge with the Roadrailers was piggyback loading gauge, not container loading gauge.

That's what I compared, too (with a typo: should be 9" for Terminal Anywhere, not 9'): whether the semi-trailer carries containers or not is not the issue here. (I couldn't find figures or drawings to estimate the lifting height of normal Roadrailers.) Lifting 230 mm above rail is not that much, and it actually appears somewhat less in practice due to the difference from spring suspension and tire deformation of the trailer road wheels (and possibly also because it appears as if the front part of the trailer is lifted less, something like 2").

Can you find figures on RoadRailer lifting heights? The Wikipedia photo appears to show a lower lifting height than Terminal Anywhere (my rough visual estimate is 150 mm), but it's not clear to me whether the other end of the trailer is lifted already.

the original Roadrailers of the 1950's had bogies that lifted up out of the way when on the road

There is a modern version, too: American Surface Lines' RailMate, but I suspect anything with deadweight carried around is a stillborn idea.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Wed Jul 18th, 2012 at 02:01:25 AM EST
[ Parent ]
Well, it was the case with Royal Crown through Mark IV, so not exactly stillborn ... its just the gas cost is not worth the flexibility of being able to leave from one railhead and return from a different one. In practice, they come back to the same railhead where they left the rail to hit the road.

I'd assume that the separate bogies are also worth some increase in top speed.

Here's an almost end-on view of a Triple Crown Roadrailer consist:


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

by BruceMcF (agila61 at netscape dot net) on Wed Jul 18th, 2012 at 12:09:13 PM EST
[ Parent ]
RailAnywhere is a chassis that holds a container, so its about extending the Roadrailer system from bimodal to true multi-modal. You could load a consist of those chassis on a rail loading track dockside and then split them up to separate destinations thousand of miles away at different road/rail railheads.

The chassis means that the bottom internal floor of the container is higher above the rail than with the original Roadrail approach, but for standard containers & singlestack, clearances are not such an issue.

When just replacing piggyback, there isn't a separate chassis, just a bogie holding up the trailer, with the trailer specialized for running in both modes, and the internal floor of the freight trailer is closer to the tracks than with any piggyback railcar.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

by BruceMcF (agila61 at netscape dot net) on Wed Jul 18th, 2012 at 12:20:55 PM EST
[ Parent ]
RailAnywhere is a chassis that holds a container, so its about extending the Roadrailer system from bimodal to true multi-modal.

Are you sure we are talking about the same thing? On the official site of RailRunner, all photos and graphs of the Terminal Anywhere system show a bi-modal system consisting of semi-trailers specialized for running in both modes (chassis with road wheels and fifth wheel coupler on and with specialised ends for railroad mode) and bogies only. The only difference seems to be that in Terminal Anywhere the trailer is lifted by being pushing up a slide on the bogie, while if I read my sources right, in classic RoadRailer the trailer is raised by active operation of its suspensions. Here is a RailRunner video showing both the jacking-up and jacking-down of a semi-trailer on the bogie:

It doesn't appear to be any higher than a standard North American semi-trailer or a Triple Crown trailer, either,having similar fifth wheel heights and being 13,5' high when loaded with a high-cube container (which would be 11 cm higher than a standard European semi-trailer, however, so they'll need to modify the trailers if their tentative European export plans are to come to anything).

BTW, what is the top speed of classic Roadrailers on rail?

closer to the tracks than with any piggyback railcar.

Quite likely, but by how much? 50 mm, 100 mm, 150 mm? Again, do you have any figures on the wheeled end lifting height? I again couldn't find any, even with the Triple Crown help. Here I find a good side view, but the 135 mm I estimate between road wheel and rail (based on the trailer interior height data) isn't really useful.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Wed Jul 18th, 2012 at 01:58:14 PM EST
[ Parent ]
Are you sure we are talking about the same thing? On the official site of RailRunner, all photos and graphs of the Terminal Anywhere system show a bi-modal system consisting of semi-trailers specialized for running in both modes (chassis with road wheels and fifth wheel coupler on and with specialised ends for railroad mode) and bogies only.

Yes, and those semi-trailers are composed of two parts: a chassis that accepts standard containers, which holds the freight. So the internal floor to internal ceiling dimensions for the freight capacity are determined by the container used, whereas with the Roadrailers, there is no separate chassis and freight container, its an integrated unit, and the internal floor to internal ceiling dimensions for the freight capacity are whatever you build it to.

Indeed, if there is a more "rounded" loading gauge in the target network, the top of the Roadrailer trailer could be made higher and the freight capacity larger by putting the top higher than a rectangular box will allow, and slanting the sides near the top.

Now, I presume that the Roadrailer is designed within the AAR standard loading gauge, but so long as it fits within the STRACNET loading gauge:

... if there is a loading gauge constraint on some shortline between the STRACNET corridor and the origin/destination loading dock, it can just hit the road.

Railrunner may well have to work through European loading gauge issues if they are aiming for the European market. Its not likely to be a binding constraint for them given the standard AAR loading gauge to work with. A conventional Roadrailer would not be the same challenge, as you just design the trailer dimensions to suit the target market.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

by BruceMcF (agila61 at netscape dot net) on Wed Jul 18th, 2012 at 03:40:05 PM EST
[ Parent ]
Ah, so you meant to differentiate between container-carrying and standard enclosed semi-trailers? However, that's not a core difference between RoadRailer and RailRunner's Terminal Anywhere technology (particularly if I interpet RailRunner's note about "a trailer solution can also be made available" right), and I don't think there can be that much difference in freight capacity.

IMHO the limiting factors in a US context are not AAR- but road-related: the 13.5' outer height limit and the standardised 47-49" fifth wheel height. So the front end external height of the cargo-holding structure cannot be larger than 115". A high-cube container is 114". So what about the inside? Checking figures, high-cube container internal height is 106", while Triple Crown dry vans have an inside height of 110" at the front and 112.25" in the rear. So in effect the 4" thick bottom of the container (about 10 cm) and a slope 2.25" high at the end is what's gained.

If RailRunner (or any new RoadRailer version) comes to Europe, they'll need to lower their stuff by about 10 cm to fit roads, but fortunately that won't reduce the cargo height: both the road vehicle height limit (4 m or about 13'2") and the standard fifth wheel heights (seem to be between 950 and 1,150 mm, or about 37" and 45") are lower.

if there is a more "rounded" loading gauge in the target network, the top of the Roadrailer trailer could be made higher

If a trailer is designed to fit the rounded corners of older railway loading gauges in Europe, then it will have a smaller capacity than a standard road trailer while already being more expensive as a special rail-ready construction, and thus be at a disadvantage.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Fri Jul 20th, 2012 at 05:01:14 AM EST
[ Parent ]
IMHO the limiting factors in a US context are not AAR- but road-related

That's what I said ~ its not an issue that has had to be considered in the US context, given US common loading gauges.

If a trailer is designed to fit the rounded corners of older railway loading gauges in Europe, then it will have a smaller capacity than a standard road trailer while already being more expensive as a special rail-ready construction, and thus be at a disadvantage.

But if it has the potential to extend the advantages of a Roadrailer in operating costs per trailer (labor/fuel) from the southeast of England into the Midlands or the North / Scotland, they could well be the dominate advantage. It depends on the number of trucks required to carry the freight ~ when you start combining the labor savings and the fuel savings for an eight trailer load, it starts to add up.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.
by BruceMcF (agila61 at netscape dot net) on Fri Jul 20th, 2012 at 02:22:23 PM EST
[ Parent ]
I see a 1999 info sheet (pdf) for the Triple Crown rolling stock as 55mph (88km/h) empty, 60mph (96km/h) loaded. I don't know what the practical speed limit would be for the design in general, as there isn't market pressure in the US to go any faster. A Cargosprinter style consist would have the advantage of distributing braking along a train, which is what limits Roadrailers to either a unit train or a unit of Roadrailers at the end of a train.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.
by BruceMcF (agila61 at netscape dot net) on Wed Jul 18th, 2012 at 03:54:38 PM EST
[ Parent ]
Could you expand on the braking comment? From what I read, in both the Triple Crown RoadRailer and RailRunner's Terminal Anywhere, the trailers have an inbuilt railroad brake hose and bogies are braked, so braking is distributed. (The brake connection is shown in the RailRunner video.)

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Fri Jul 20th, 2012 at 05:06:11 AM EST
[ Parent ]
OK, I may have misread the information sheet I linked to. On re-reading, it talks about the Roadrailers not having manual parking brakes. Rather, they have brakes engage when a certain time interval has passed without pressure on the brake hoses.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.
by BruceMcF (agila61 at netscape dot net) on Fri Jul 20th, 2012 at 03:45:58 PM EST
[ Parent ]

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