garden railway level crossing for pedestrians
Strong enough to walk on, nothing to trip on after a few beers (other than a passing train)
Used sieved concrete, took all the big bits out down to about 6mm.
Bed of gravel about 20mm. A simple mesh of light reinforcing steel i had lying around is laid on the base, after getting the worst of the rust off. About 50mm of concrete, floated smooth-ish. laid one pour to base of track level. As soon as stiff enough to sit track on it without sinking, poured a slightly runnier mix over the track. Very tricky maintaining alignement and levels. one end was about 10mm low, rammed underneath to bring it up, fixed the cracks on the concrete with a light pour of cement. So far stable (fingers crossed).
We may have a warning light for pedestrian traffic one day :)