Have you ever watched the Disney Skyliner gliding through the sky with empty gondolas and wondered, “Why on earth are they running it with no one on board?” Or maybe you’ve been stuck in line and they let empty gondolas pass by unfilled. It can be quite the head-scratcher. The Skyliner seems to be working fine, just let us hop on already!

So, what’s the deal? Did someone have an, um, accident in the cabin? Or maybe they’re teasing us?

Actually, it’s neither. Here’s the scoop.

One day, while we were waiting in line for the Skyliner, the call came in to shut it down due to bad weather. With nothing else to do, I started examining the gondolas at the station. That’s when I noticed something curious: some gondolas had lights near the door, some green and some red.

Intrigued, I approached a nearby cast member and asked about the lights. What he told me was fascinating.

Each gondola, it turns out, is equipped with a GPS and an emergency call system. In case of an emergency, these systems provide notifications or instructions to passengers. They also play scripted messages as the cabins pass by points of interest, like, “Today, we’re traveling through one of the many protected wetlands here at Walt Disney World Resort!”

But here’s the kicker: unlike streetcars or subway trains, the Skyliner gondolas don’t get their power from the wire they hang from. Instead, they have a battery (or supercapacitor) pack that charges while the gondolas are at the station. When they’re up in the air, they’re running on their own power.

The lights on the outside of the gondolas indicate the charge level to the cast members.

Green means the packs are fully charged and ready to go.

Red means the packs have enough charge for the GPS and emergency call system, but the scripted callouts are turned off to save energy. Ever taken a ride and it seems quieter than usual? Now you know why!

No light means no charge. For safety reasons, passengers usually aren’t allowed in these cabins.

So, how long does it take to charge these packs? According to the cast member, it takes about five round trips to fully charge a pack, with each trip lasting around 15 minutes. That’s over an hour to charge a cabin!

The secret hinted at in the title is that Disney runs the Skyliner even when it’s empty to keep the power packs charged. If they didn’t, the cabins would lose power and pose a safety risk.

When you see the Skyliner running empty, it’s so they don’t run on empty.