Is it a newer building? If it was installed within the last 10 years it could be a MRL(machine room less) elevator. With an MRL everything is installed within the hoist way including the machine and brake. On older installations the machine and brake would be installed in a separate room typically above the top floor of the building where there would be a thick concrete slab between the machine room and hoist way. With this set up often you wouldn't here the brake picking because it would be separated by the floor slab and in a different room. On the MRLs you can here everything within the hoist way including the break picking just before the elevator takes off.

I have been asked the same question from some of my customers when they compare the sounds coming from a new MRL to an older installation with a overhead machine room.

The reason they typically install MRLs now days instead of having the equipment in a separate room basically just boils down to less cost when they don't have to construct a separate room some where else in the building. And trust me most of us in the industry don't care for MRLs either when it comes to the maintenance and repair aspect of it.

I should clarify just because you have a machine room or equipment room on a newer installation it could very well just house the elevator controls while the machine and brake reside in the top of the hoistway.