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The most often seen configuration in the US, as far as doubles go, is an A-train with two 28 foot pup trailers. On the back of each trailer, there'll be a pintle. A converter dolly will be attached to this pintle (basically an additional axle and fifth wheel), and the second trailer will be connected to this. These are most commonly seen in use with LTL companies such as Yellow, Roadway, FedEx, UPS Freight, Old Dominion, etc., although not exclusive - general freight carriers such as Averitt Express, Swift Transportation, Central Transport, etc. have them, as well, although in more limited numbers.
There are other types. In the US, some LCV (long commercial vehicles) are permissible in some states. Examples include the Rocky Mountain double (45 ft. trailer with a 28 ft. pup behind it, usually attached in an A-train configuration), turnpike double (two 45ft trailers, connected the same way), and triples (three 28 foot pup trailers).
Some states use B-trains, in which the front trailer has a fifth wheel on the back end of it to which the second trailer is attached. In the US, it's usually a 45 foot trailer with a 28 foot pup behind it, and these configurations are common in Michigan, northern Indiana, some parts of Upstate New York, and all throughout Canada. In South Africa, we usually had combinations of two 40 ft. trailers. Australian road trains are typically B-triples.
Finally, there's the C-train, which, to the best of my knowledge, isn't commonplace in the US, but is more so in Mexico, Canada, and elsewhere. A C-train is similar to an A-train, but, instead of using a pintle and clevice as the A-train does, it uses a drawbar which attaches to the rear of the first trailer. This eliminates one pivot point in the combination (the drawbar is rigid, and does not turn when attached), and allows for these combinations to be backed up. I personally wish they would outlaw the A-dollies in the US and make the C-trains mandatory, because it's also a more stable platform than the A-train.
What else can I help you with?
Which shut off valves should be open and which closed on a tractor trailer?
Closed on the first trailer in set of doubles. No on the middle trailer. No of a set of triples
Can you pull doubles with a single axel semi tractor?
Yes
Does chesapeake bay bridge tunnel allow tractor trailer doubles?
Yes.
What is the gas mileage of a farm tractor?
The gas mileage of a farm tractor depends on the model, the year, the condition, and the land driven on. There is no set gas mileage to be expected from a farm tractor.
Which trailer should be first behind a tractor?
If you're pulling doubles or triples, it'll be the lightest one.
What is the width of a 1566 International tractor with dual wheels?
Depends how wide the tires are set
What is the towing capacity of a 2006 freightliner 6x4 tractor?
Depends on the specs of the tractor. The 6x4 tractor spec'd to never haul more than 80k gross and the 6x4 tractor spec'd to pull those B-train doubles and eight axle sleds in Northern Indiana and Michigan aren't running the same drivetrain, I can assure you of that.
How do you change the governor on a john Deere L120 lawn tractor?
How do I set governor on a johndeere l120
How to set timing for Allis Chalmers CA tractor?
timing order is 1-2-4-3
What are the points set at on a 1949 tractor?
I would start out at 15 thousands, that's standard on most motors,
What do points set at on a Massey Ferguson 202?
mf 202 industrial tractor with Z134 engine is .022
What is the average price to have a set of used tractor tires retreaded?
The average price to have a set of used tractor tires retreaded is around $100 - $150 dollars per tire. Retreaded tires should only be considered if the tires are less than 5 years old.
