What is "pick up speed"

Usage examples of "pick up speed".

She chastised herself, and began to pick up speed again, pushing her legs faster and further.

A sparkler ignited behind it and it began to pick up speed, heading inward toward the orbit of Pluto.

Troy grabbed her arm, and together they leaped from the cargo pod as the train continued to pick up speed.

Then the 'ware finished reprogramming the muscle bands, and she began to pick up speed.

Outside the stateroom's large picture window the roofs and spires of Chrystianaville slipped past, slowly at first, but then faster as the line train began to pick up speed.

Quentin had completed its turn now, and Ferrol felt himself being pushed back into his seat as the calf began to pick up speed.