To begin:

Capacity, defined as an amusement park term is how many people can be sent through an attraction/ride/show per some unit of time.

Disneyland has over 50,000 visitors on an average day, yet most of the lines stay 60 minutes or less. How is this possible?

By making high capacity attractions for the park.

Here's some ways they manage to have most rides be able to go throughmore than 1,000 people per hour:

Split Loading Stations:

Invented by Arrow Dynamics, this concept allows for two train to be loading and unloading at the same time essentially doubling the ride's capacity. This method is used on:

Indiana Jones
Big Thunder Mountain
California Screamin'
Small World

Another method of keeping the guest flow high and wait times loww is Disney's Omnimover technology, which is a "never ending train" of cars linked together that move at the same pace constantly.

This system can load 4 people every second. That's 240 people every minute, and well over 1,000 each hour.

This is used on:
Haunted Mansion
Astro Blasters
And new this year:
Little Mermaid

Another method is the multiple train same time loading used on:

Space Mountain
Monsters Inc.
Splash Mountain
Pirates Of The Carribean


I hope you come to appreciate how much work goes into getting you on these rides!