Glossary
Machine-Room-Less (MRL)
A machine-room-less elevator has no separate conventional machine room; equipment may be in the hoistway, pit or an adjacent cabinet.
MRL can describe a traction or hydraulic arrangement. Traction versions commonly place the motor and machine near the top of the hoistway. Hydraulic versions may place controls and valve access in a hoistway wall or door frame.
Owners still need code-compliant access, working clearances and environmental control for the equipment spaces. For project context, compare traction and hydraulic elevators and check the adopted requirements through Elevator Codes and Regulations.
Sources
Washington State definition of machine-room-less elevator; Wisconsin DSPS guidance on MRL equipment location.