Loaded by Forklift
One of the more amusing stories involved picking up a steel beam for a construction project I was involved with. The steel yard thought it was necessary to use a forklift even for this load that was being placed on a bike trailer.
Among the heavier loads was this pile of 16 concrete blocks for someone who posted a request on freecycle site. The distance was only 4km along flat ground.
16ft Floor Joists
For a house addition, it was necessary to deliver over a dozen floor joists. This bike trailer was at the edge of it's capacity, but succeeded in getting the material on site with no problems.
A woman that I knew wanted to pick up this cabinet from Goodwill, but the piece wouldn't fit in her full-sized van. Thankfully a bike trailer doesn't have any size contraints for a load.
A group of people were planting trees along a car-free path and found themselves struggling. However with the help of this bike trailer, it became vastly easier to move materials back and forth.
150kgs of Food
A local company donates regularly to a non-profit that I'm involved in. One week the food donation amounted to roughly 150kg (300lbs). So it was helpful to have a friend along and split the labor.
How do you haul delicate items like this? The answer is to use plenty of padding between each door panel to reduce vibration. In this case I folded burlap sacks which I had on hand beneath each corner.
Be sure to take bumps slowly and watch for potholes.