Jewell train

In railroading, a Jewell train is a train which is composed entirely of locomotives and hauls no cars. Many railroad crews enjoy operating this way because it makes the engine easy to control and they are not responsible for a consist. However, most railroads do not like to operate locomotives this way because it burns fuel without hauling cars, and thus generates no revenue for the railroad. Therefore, most Jewell trains are en route to pick up a consist or other equipment, or en route for repairs.
Some railroaders also know these as light engines or light power.