The hesitation definitely meant she needed a little kick to the butt to move.

"I've put you through worse," said Raph quietly to Nico as he dragged her by the arm to get her moving and running alongside the train. "Grab, kick off the foothold, and swing in. I'll catch you if you fall."

The tracks were elevated so there was no risk of falling and getting squished by the train. There was risk of falling back to the roof pretty hard.

"You got this."