The two main ones in service are the traction and the hydraulic. They satisfy almost completely different requirements and should be installed accordingly. The traction elevator lifts the car by cables, using counterweights to minimize energy expenditure. The hydraulic elevator pushes the car up on a shaft filled with compressed oil. Hydraulic elevators are considerably slower than the traction type, having a speed of 30 to 50 mpm whereas traction elevators operate at faster than 70 mpm and even in excess of 300 mpm.
Hydraulic elevators require less space for machine rooms, which can be remote from the hoistway.
Figure 2 shows sections for comparable hydraulic and traction elevators. Sectional elevations of elevators Car Size and Shape Elevator cars are rated according to maximum allowable weight and number of passengers. Usually, however, the maximum loading of an 1150 kg elevator will not exceed 13. The shape of cars is relatively uniform, depth being about two-thirds width. This minimizes the time taken to exit from a full car and reduces transfer time, but the entry and exit of wheelchairs and equipment may thus be made more difficult.