This is the original bridge as posted a couple of months ago - four inverted PC stands, resting on bricks.
We’ve added a similar structure, with a slight dogleg in the middle. This one rests on steel cut from an old table, concreted into the ground.
At the end of the new piece, we’ve placed a 12’ long steel ramp. It’s two 6 foot long pieces of channel that used to be the sides of a frame that held switches for a computer network. They’re held together with a secure but flexible join that allows the slope of the first and second sections to be different. For the experiment I’m planning, the first section slopes at just under one degree, while the second slopes at six-and-a-half degrees.
The switch at the top leads to a spur atop the retaining wall (5 degree slope) and a spur along the fence.
Details on the experiment to come!