I see a lot of a train trailers here in Wyoming.how do the weight calculations work .number of axles etc. Can somebody fill me in. Thinking about buying flats to haul hay out of Montana. Would I need a tri axle tractor. What would you be. Tagged to haul. Weight wise
You can gross 117K on the interstate. MAX trailer(s) length is 81' including any overhang. If you need to overhang, do it in between trailers, not at the end or front. If you are just hauling hay you may not need a tag axle, as you may run out of room before you approach 117K. The bridge formula/chart in the front of an atlas will tell you weights and axle spacings. You will need to measure EVERYWHERE. The one that will be your biggest limiter is "inner bridge", you want as much space as you can between your lead tandems and your pup front axle. A way around this is to run 2 axles in the front of your pup. I would look for a pair of 38' trailers and make your dolly tongue as long as you can, keeping overall trailer length at 80' 11". You can also go shorter with a longer tongue - I don't know how much deck space you need. Try to get at least 1 of the kingpins set back a bit - maybe 30" or so. This will give you more latitude on your inner bridge. However, with a kingpin back at 36" or more, the pup will be prone to rollover if you turn tight while offroad. A tandem dolly will help here. On secondary roads you can go 149K if you have both tri axle trailers and a tandem dolly with a tag on the tractor. I think you are still limited to 81' of trailer. I only run 117K and don't know all the details of the secondary roads. The Sheridan scale can be sticklers on the bridge weights, Laurel isn't too bad, Frannie is OK, but Belt, MT can be picky also.
I am not familiar with a trains, as they are legal here, but are only allowed 80,000 gross. I am very familiar with hauling hay on tractor trailers, and I have never seen a load approach being limited by weight, they always cube out long before then.
Thanks for all the info. I will check my atlas too. Trying to figure out weather I can make some money hauling hay to the ranchers around Meeteetse where I live. They seem to be short of hay and bring in a fair amount for the winter. Got a 9900 IH with a 550 Cat and 18 speed but it isn't a tri axle.
Where are you bringing it in from?? I live in Clark. If you are coming from western MT, you will miss the Laurel scale, if you come thru Clark you will miss the Frannie scale. MT does set up their portable scales all over the place, usually not in the winter - we wouldn't want DOT to get frost bite :notworthy. I would make a few runs before you decide to get a tag axle on the tractor. Like Mitch said, you will likely run out of deck space before you hit 117K (or 108K w/o a tag axle or with a single axle dolly/pup). All flat beds are different, but lets just say a 38' steel frame goes 10-11K. Your tractor is around 18K, so total empty weight might be 40K. Statutory height in MT/WY is 14', your deck height will be around 4' unless you run drop decks. So you can go 10' up and 75' long. Can you fit 75,000 of hay in that space?? These are round numbers but it will give you an idea if you need a tag or not or if you need a tandem in the front of the pup.