How about a double articulated set-up with trailer+electric trailer+diesel tractor unit. 
https://www.youtube.com/watch?v=qYAmFWGZI1I
i would think that having an unsteerable power source was a bad idea also what does it weigh because once you have done your 250 miles you still have to drag it along now adding to the work the engine has to do.
22000lbs 11ton. Revoy electric trailer rolls into Port of Stockton, CA
I guess it depends on exactly how the contract works, but it sounds like a very low risk for the truck operators, and no outlay. They can try it out and (contract dependent) if they donât like it, walk away.
25,000 miles a month? OK they operate a lot differently over there but that sounds pretty decent to me. And if they need more, just drop the batteries and go dino juice all the way.
Always the possibility of Government changing weight regs too if needed to encourage take up.
The devil is in the detail, and I doubt it will survive forever, but it could take off in the medium term.
Wouldnât want one of them in snow or ice-cart pushing the horse was never a good idea!
Depending on exactly how it is setupâŚ
The video shows that the power module is steerable, and shows it moving the trailer without a prime mover.
So, combining the two features could we have the truck being detached and an operator driver or depot staff manoeuvering the trailer onto a dock without the truck, only using the smaller and more agile battery pack? Walking with a remote control pack.
obviously i have never driven a multi trailer set up how do brakes normally work on them.
I also would of thought that getting the two engines balanced wouldnât be easy
It really doesn`t matter much in a multi axled set up whether the axles are on different vehicles or not. What mostly matters is the axle loading (the weight on the axle).
The video suggests that the battery motor unit uses king pin loading as a âthrottleâ. If the unit is being pulled hard by the truck it puts more power in, if it is pushing the truck it can use re-gen braking to slow down and power up the batteries.
With regards to the extra weight of the electric unit, the government might increase the gross weight by the weight of the electric unit so it can still carry the same payload. Thatâs what they did when a company fitted an auxiliary power unit on a tractor as the driver cannot run the engine to keep warm/cool when on break in most states.
That was my thinking too. The extra weight, on an extra axle, no big deal?
No night heaters in the US? We commonly have diesel fueled air heaters here.
Some of the colder countries heat the whole engine with either diesel or gas auxiliary heating systems.