To reach the deep underground vaults of Gringotts Wizarding Bank, a goblin whistles for a small cart in which he or she and the visitor ride.
The cart is self-propelled and apparently steers itself along the underground passages, because the goblin doesn't steer as it winds its way along railway tracks in the floor. The cart has only one speed: "breakneck" (PS5).
Harry, Hagrid and Griphook rode in a cart together on Harry's first visit to Gringotts. Hagrid did not enjoy the ride at all, asking Griphook if the cart went any slower and looking 'very green' when they alighted. (PS5)
Harry, Ron, Hermione, Griphook and an Imperiused Bogrod made a journey in a cart to Bellatrix Lestranges vault when they broke into Gringotts to acquire Hufflepuffs cup. (DH26)
In the Wizarding World of Harry Potter at Universal Studios, there is a ride called 'Harry Potter and the escape from Gringotts'. You get on board a Gringotts cart and take a ride through the underground vaults.