“I’ll hold the class,” he said. “But I won’t call anything unsafe without seeing it myself.”

Grant stared. “You can’t do that.”

“I can. I have the flags.”

A marshal lifted the red flag. The crowd murmured. Children already wearing helmets began asking their parents why the exhibition had paused.

Leo climbed out of the cart. He looked furious and betrayed. “Caleb, what did you do?”

“I asked for time to check the machine.”

“You promised to help me race!”

“I am helping you race as safely as we can.”

“That’s easy for you to say. You’re not the one who’ll have everybody laughing at him.”

Caleb had no answer that would make the teenager’s humiliation disappear. He had been that age once, when one failed performance could feel like the whole world. He took Leo aside where the crowd could not hear.

“I’m not asking you to agree with me,” he said. “I’m asking you to watch the test, and then tell me what you think.”

Leo glared. “And if the test is fine?”

“Then I’ll say so publicly. Even if I look foolish.”

Odessa asked Grant what mass he had used for the previous trials. Grant supplied a number. It was much lighter than Leo with his helmet and protective vest. Odessa asked about lateral loading; Grant said the design was proprietary. Caleb asked whether Grant had measured the brake linkage while the carriage leaned. Grant replied that the tests were confidential.

Reuben finally spoke. “A proprietary answer doesn’t stop a cart at the bottom of this hill.”

The demonstration took place in the upper staging lane, not on the full downhill route. Volunteers removed the wheels from a spare cart and assembled a simple weighted frame to imitate Leo’s seated load. Grant insisted on positioning the black cart himself. Reuben tied a broad control strap to its front tow point, placed two blocks behind the wheels, and ordered everybody behind a chalk line.

When the load was added, the rear carriage settled noticeably. Reuben asked Leo to move the steering wheel left and then apply the brake while the cart remained blocked. The first attempt sounded normal. On the second, Caleb heard the familiar click from the underside. The rear left wheel shifted inward. The right rear tire lifted a little from the pavement.

Odessa pointed silently. Nobody needed an elaborate lecture to see that a braked wheel should not rise above the road while the cart was stationary. Reuben repeated the motion with the brakes released. The wheel stayed down. He repeated it while applying the brake gradually. It lifted again.

Grant hurried forward. “The blocks are changing the load path.”

“Then show us how,” Reuben said.