Using "chain gang" labor is fraught with liability problems, as the Fort Collins, CO, trolley operation found out when one of the convicts was injured while working on their track. And you would probably only get minimal work out of them anyway. A certain RR museum in CA thought about using them (a work-release facility was nearby) until they realized that it was apt to result in future theft of their tools and equipment, once these guys saw what the museum had.