You could have pedaled that Cryptorider
Factor in the rolling resistance and you would be brave to "pedal it" without an engine. With 6 trailers attached, the whole combination slows down decending a hill without engine power.
In the beginning i was thinking of methods to add trailer brakes to the assembly but after the first test ride with some weight added to the trailers, it became obvious that there was a fair amount of rolling resistance. The 9 inch front disk rotor and 6 inch rear disk rotor stop the trailer train in a hurry when required.
One day i'll make a video of the 6 trailer train loaded as heavy as possible on a reasonably steep hill. With a few extra modifications, i'm thinking that a good 300 kilos (660 ponds) can be hauled in low range 1st gear; hauling firewood to the car trailer.
As things are, the 6 trailer train holds (by the maths) 1/3 of a cubic meter (0.39 cubic yard) without hungy boards on the smaller bicycle trailers. The car trailer holds 2.4 cubic meters (3.12 cubic yards) and the last time i filled the car trailer using the trailer train, 8 trips were required for a full load.
It must be remembered that the bike wasn't hauling paper light softwood but properly heavy hardwood. With hungry boards on the bicycle trailers i'm confident i can get the cartage capacity up to 1/2 a cubic meter (.65 cubic yard).