Works as a new MCV, but cannot build other Crusher Cranes
The crusher crane is a multi-purpose Soviet structure in Command & Conquer: Red Alert 3. It functions as material recycler for the Soviet war cause, a stripped-down construction yard, and to repair vehicles.
One of the Soviet mantras is efficiency, and that word has developed into many things: among others are cheap labor, mass production, industrial plants and pure efficiency. During the early Soviet industrial development, the Soviets must deal with many defective, wrongly designed, or "undesirable" products. Simply disposing of them requires cost for the establishment of disposal grounds and landfills, and is very inefficient. Instead they begun recycling the undesirable, reprocessing them back to ore, the basic material, to create 'new' products, be it new rifles for Conscripts, shiny new rotors for a Twinblade, or tank armour to create the Apocalypse Tank. So thorough (and of course, efficient) of these thinking that the military brought them into the war, by introducing the crusher crane and, later, Grinders.
The grinder is a structure unique for the Soviets. The crane is basically one with crushing machinery surrounding it. The crushers grind any vehicle and every vehicle that comes into contact, recycling them into Ore, which would be used to create another Soviet war machine. The cranes also help in construction of structures within their range, which is less than that of a construction yard. The components used to construct these cranes require special treatment to guarantee that the grinding teeth have enough durability to "recycle" anything. As such, only the Soviet Construction Yards have the required machinery to construct parts for the grinder. Repair drones are assigned here to repair friendly vehicles battered from previous brawls. It enables an extra structure and defense build queue, automatically repairs all units within the radius of its repair drones, and it can crush units directed into it for cash. It only grinds up non-infantry ground and naval units (terror drones included), unlike Yuri Grinders.
Building a crusher crane is a good idea if rapid base expansion is desired, as one can build 2 or more structures or defenses simultaneously. This may allow the Soviets to build up their base much faster than the Allies or even the Empire of the Rising Sun. The crusher crane build queue cannot construct other crusher cranes however - only the construction yard build queue can do that. Doing this will cost a lot of ore credits however - plan wisely.
Like the construction yard with their own internal power facility, crusher cranes will remain active even in low power situations, but they will however build slower. It can be built on water, facilitating repair of ships and submarines.
It should be built at the start of a level, even before a Reactor. When finished build a Reactor and a Barracks immediately, then 2 Ore Refineries simultaneously. Base defenses can also be built (be sure to buiild more Reactors for this). When no longer needed (when you have all structures up), it should be sold for cash. If you have lost your MCV though your Crusher Crane is still intact, you may use it to build a new MCV by building or having a War Factory or a Shipyard, then a new MCV.
Behind the scenes
The Crusher Crane is similar to the GDI and Nod Cranes (construction ability) and Yuri Grinders (grind units for resources). However the grinder teeth can only crush vehicles, unlike Grinders which crush any ground unit. As an added bonus, the Crusher crane is structurally amphibious, enabling it to be built over the waters and to repair/grind ships.
Crusher Cranes can crush any unit to be recycled for cash. Strangely, even the pilots of the vehicles themselves get crushed.