Bill Tindall, E.Tn.
What is on this steel are bridge ties- 8 x 10 x 10'. No way to manually carry and position them with only 14" I-beam flanges to walk on.
A rubber tired fork lift carries the ties out on the bridge deck as you see it in the picture (just ties and runners). A small excavator with a grabber opposed to the bucket snatches the tie from the fork lift tines, then swings it around into position. It is slow.
On the last bridge which was shorter and spanned a road, we set a crane in the road and positioned 100 ties in less than half a day.