List of largest locomotives

As railroads around the world haul larger quantities of freight efficiently, the title of world's largest locomotive has often been passed to new generations of rolling stock. Currently, with what information is published, the most powerful articulated and single unit locomotive is the 2ES10S (3ES10), the strongest-pulling is the IORE, and the heaviest is the Union Pacific Coal GTEL. The information is incomplete on some locomotives (for example, the BJ 6001), thus, the current leaders listed in each category may not be the actual leaders.
Standard.
There are many ways in which a locomotive can be the largest: the heaviest, longest, most cylinders, most power, or most wheels. It is often defined as the longest in length, but there is even a debate on whether or not to include the tender, which is equivalent to the fuel tank of a diesel, in the measurement. To establish the "largest" category, several factors take precedence: overall weight, which gives traction over driving axles; size (length & height of engine itself); and power, which may be in terms of raw horsepower, tractive effort, available power at axles (shaft horsepower) or, in the case of steam locomotives, available steam on a sustained basis.