Instructions can be found here on Amazon as paperback and kindle app for smart devices. This was a particularly fun build to develop as I haven't seen anything like it in Lego before so I wanted to build it for my own collection of vintage and unusual rolling stock.

As for history, cement powder used to be air blown into canisters like this and then hauled by train. At the destination, they're then emptied by air and sent back for more cement powder.