How crane workers stay so fit

Amtrak's parked what looks like a battle crane train on a siding at Readville station in Hyde Park. It has some instructions for how to signal the crane operator to move the thing plastered on one side.

The tall crane in the rear is paired with a similar crane on the other side of the Fairmount Line tracks and looks set to lift that blue bridge into place to replace the old Erector Set-style bridge that the line now more or less ends at.