There are now a number of ways that DCC can be used to control working accessories such as cranes and turntables and manufacturers are now producing models with inbuilt DCC decoders - some examples follow:

The Uhlenbrock 80000 HO Gantry crane with 80020 electro magnet 1.Product 2. Film

The Uhlenbrock 80100 HO Water Crane 1.Product 2. Film

Roco 40110 Portal crane and electro-magnet or 46807 grab 1. Product 2. Film 1 Film 2

Uhlenbrock DCC Digital Servos 1. Product 2. Film of digital servo used with a semaphore signal.  Film of Digital Motor

Uhlenbrock DCC Digital servo decoders 67800 used on the Holcombe Brook and Tottington layout to give semaphore signals a realistic bounce :

There are now also products that allow you to digitize operating accessories.  For example LDT make a decoder that will convert a turntable to DCC  LDT Turntable Decoder. 

Film - Setting up the LDT Turntable decoder:

Uhlenbrock produce a decoder to control a motorised crane with Two motors and up to four additional switched outputs  Uhlenbrock 67900