If you ever get tired of OTR and seek work for an LTL carrier that will get you home more often, chances are you'll be required to operate double trailers. Double trailers or pups as some call them are usually 28' long which totals to 56' of space; a little longer than a 53' van and still only needs 5 axles. They are usually pulled by a truck with one drive axle (single screw) and they have a converter gear (dolly) which is the axle and 5th wheel assembly that hooks to the back trailer and of course, both pups have a single axle.
When it's time to latch 'em and snatch 'em, this is what you do:
- Identify the two trailers you'll be taking and the weights of each.
- The heavier trailer goes up front so the dolly needs to be spotted in front of lighter trailer.
- Hook up dolly to your bobtail tractor; you should have a pintle hook on the back
- Back up to second trailer and spot dolly in front of it and align with king pin.
- Make sure trailer height is correct for coupling; adjust landing gear as necessary.
- Hook to first trailer and back up to dolly, aligning both trailers and dolly.
- Lift dolly and hook up to front trailer and secure with chains and pintle hook.
- Back first trailer with dolly under second trailer to securely couple; give a forward tug to confirm connection.
- Hook up air lines and electrical cord
- After a full pre-trip inspection, you're ready to roll!
Here are some things to be aware of when operating doubles.
- Don't get in a situation where you need to back up. I have backed them up, but it's nearly impossible.
- If taking a break at a truck stop, be very careful you don't go down a "dead end" row. You must be able to pull through a space or just pull through fuel island and get in and get out!
- The back trailer is very sensitive to steering wheel movements. This is called the "whip effect". When you jerk the steering wheel, the physics of that motion is multiplied to the rear trailer and that trailer will respond with more movement than you'd think, hence the term "wiggle wagons".
- A set of doubles tracks better than a 53' trailer, meaning you don't have to take your turns as wide. The overall combination is around 8' longer with the 56' of trailer and the space between the first and second trailer, but it will still track better than a 53' van.
There is more to know when operating this type of unit, but these are the main points. I recommend that you get your doubles endorsement in order to make yourself more versatile and attractive to prospective employers.
A special thanks to TruckStockImages.com for the use of their images.