They require a tanker endorsement, and most commodities they haul also require the driver to have a hazmat endorsement.
It's an endorsement to pull double or triple trailers.
An "H" endorsement on a Commercial Drivers License "CDL" means that a driver is qualified to transport hazerdous materials.
It seems like you're referring to endorsements. "T" is the endorsement to pull double and triple trailers. "X" is a combination of two endorsements - Hazardous materials, and tanker.
Yes you can. You can pull doubles and triples. You can pull two 48 trailers and two 53 foot trailers. You can pull three 48s, but you cannot pull three 53 foot trailers.
Yes
Yes. If it requires a tanker with an unrestricted CDL, so it does with a permit, as well.
No
Horse trailers were invented around 1960. Because most of the vehicles didn't have enough power to pull the trailers, most people didn't have them.
Yes
No. Triple trailers are not allowed on any Washington roadways.
Cattle trailers are used to securely store and transport cattle by ranchers. These trailers can range in size from accomodating one or two cows to several dozen. The trailers are attached to an SUV or truck to pull them.
The answer is NOT "4"