All constructors call NewInstance automatically. NewInstance calls InstanceSize to determine how much memory to allocate from the heap to contain a particular instance. Do not call NewInstance directly. 

TSoapDataModule overrides NewInstance to increment the reference count when a new instance is created. This prevents any constructor from accidentally deleting the instance due to a reference count of zero. The AfterConstruction method decrements the reference count after all constructors have executed. 

System::TObject::NewInstance 

System::TObject::InstanceSize 

AfterConstruction