The DRG H 02 1001 was a high-pressure steam locomotive built by the engineering firm of Berliner Maschinenbau (formerly L. Schwarzkopff) to the design of Dr L.

[1] The aim was not only to improve fuel economy—the usual reason for adopting high steam pressures—but also to increase the amount of power that could be produced within the German loading gauge.

The H02 1001 locomotive was the only example of the Schwarzkopff-Löffler high-pressure boiler system, a complex technology in which heat was extracted from the firebox by tubes filled with steam rather than boiling water.

Steam was delivered at no less than 1,750 lbf/in2 (123 kgf/cm2; 12.1 MPa) to two very small outside cylinders of 220 mm (8+11⁄16 in) diameter.

These were compounded with a single 600 mm (23+5⁄8 in) LP inside cylinder.