I’ve been reading some of the other threads on RoadRailers on the forum, about the different types, and the progression of designs for shared axles, axles that support the trailer weight on the road and on the rail, and some of the pros and cons about running RoadRailers.
I found this picture of what I think would be a current bogie to support a trailer.
From what i’ve read, it looks like the trailer tongue hooks in, and the loop towards the front of the bogie is where the trailer is pinned in to the bogie, and then each bogie somewhow connects to the other. (I’d guess that this bogie is the one that adapts the RoadRail train to a locomotive, and that standard bogies somehow connect to the rear of the trailer in front)
Anyhow, how do you load the trailer onto the bogie? I know that to couple the cab with the trailer, the driver simply backs up to it, but how would you do that with this bogie? Then wouldn’t you have to lift the back somehow to get the road wheels clear so the rear bogie can be attatched?
The air suspension of the trailer lifts the body at the rear so the bogie can be rolled under. The air suspension then lowers the trailer body onto the bogie and retracts the road wheels.
We should add that the next trailer in line connects directly to the preceeding trailer, not to the fore bogie. The RoadRailer trailers have a tongue in front and a slot in back, and the tongue slips into the slot where a link pin locks it in. Thus, all RoadRailers connect to each other elephant style, e.g. only front to rear.
For comparison, the RailRunner bi-modal technology allows more flexible connecting and disconnecting options than RoadRailer.
RailRunner trailers have slots fore and aft. The connecting tongues are fore and aft on the bogies themselves, therefore each RailRunner trailer connects directly to the bogies, not the preceeding trailer. RailRunners then can be loaded front first or back first, either way that is most convenient for the one doing the consist makeup or breakup.
RailRunners are also better through tight curves than RoadRailers, as each trailer connection to the bogies has two pivot points per bogie, whereas the RoadRailers only have one pivot point per bogie. The RailRunner bogies have radial steering which allows the bogies to negotiate curves without a hint of flange squeel, but the radial steering may end up being more of a maintenance hassle than it’s worth.
There is also a slight tare advantage of RailRunner trailers vs similar RoadRailer trailers, although at this time RoadRailers are primarily dry vans and reefers, while RailRunner is focussed on container chassis and flatbeds. Perhaps some gentlemen’s agreement going on there. <
Not living in an area where either type of unit is used very often (Botson, MA), it’s interesting looking at the two designs. I can see how the railrunner might offer better handling, and more flexibility, but I would imagine that you could have some of the same train handling problems with mixed loads (even the difference between a flatbed and a normal box trailer).
I know there is little slack action in these trains, and a lot less than in a normal train, but sometimes I would think that could be a bad thing - with slack, things get jarred a little bit, but there is room for the run in to dissipate. With no slack, any run-in of the rear end of the train gets transfered more directly through the entire train, where it might derail a lighter car more easily. I suppose though, that if you can run a mixed train of different types of cars, the same could be done here.
To me, at least, the triple crown design looks a little better. One of the big items seems to be not jaring the truck trailer because it doesn’t need to be loaded or unloaded, yet some of the trailers in the roadrailer video are clearly leaning towards one end or the other. A fast brake application could tip over a load inside the trailer.
Also, not that it’s not an advantage, but if the whole idea is for truck trailers to be able to be moved by rail, why should it matter what direction the trailer is facing? It can’t possibly take that much longer for the truck driver to do a 180 with the trailer before it’s loaded?
And, to add to that, if the trailers are facing different directions, it means that sometimes you back right up to 're left with a random bogie hanging around that needs to be moved.the front of the trailer, but other times you are backing up towards the rear of the trailer. This means that you need to go to the front of the trailer, and lower that trailer from the bogie, and then pull the trailer away. But, because only the back end of the
We should add that the next trailer in line connects directly to the preceeding trailer, not to the fore bogie. The RoadRailer trailers have a tongue in front and a slot in back, and the tongue slips into the slot where a link pin locks it in. Thus, all RoadRailers connect to each other elephant style, e.g. only front to rear.
For comparison, the RailRunner bi-modal technology allows more flexible connecting and disconnecting options than RoadRailer.
RailRunner trailers have slots fore and aft. The connecting tongues are fore and aft on the bogies themselves, therefore each RailRunner trailer connects directly to the bogies, not the preceeding trailer. RailRunners then can be loaded front first or back first, either way that is most convenient for the one doing the consist makeup or breakup.
RailRunners are also better through tight curves than RoadRailers, as each trailer connection to the bogies has two pivot points per bogie, whereas the RoadRailers only have one pivot point per bogie. The RailRunner bogies have radial steering which allows the bogies to negotiate curves without a hint of flange squeel, but the radial steering may end up being more of a maintenance hassle than it’s worth.
There is also a slight tare advantage of RailRunner trailers vs similar RoadRailer trailers, although at this time RoadRailers are primarily dry vans and reefers, while RailRunner is focussed on container chassis and flatbeds. Perhaps some gentlemen’s agre
According to a planned RailRunner move in North Dakota, a fully loaded outbound RailRunner consist of 125 units will be inbound with only 20% loads. This means they’ll probably keep the loads up front, and the empties tailing. I can’t imagine they’d try it with empties ahead and loads trailing.
You can add as many intermediate bogies as you deem fit if you want to add a little slack to the consist.
The RailRunner is the logical evolution from the RoadRailer. The RoadRailer is an older technology, the RailRunner newer. In my opinion, the next evolution in bi-modal after RailRunner will
CSX used them briefly (Cincinnati-Atlanta), but only NS through Triple Crown has put together an operating network. As has been pointed out elsewhere, they are used primarily in the auto parts trade.
Although RoadRailer and RailRunner are interesting technical and engineering developments, they are still non-standard equipment for both rail and highway, and are handicapped in that regard.
IIRC, CSX ran roadrailers Detroit to Atlanta, using F9’s to pull them. NS also ran roadrailers from Detroit to Atlanta and regularly beat CSX by a wide margin.