Donkey-drawn rail cart to cenote/underground cave

I've got a question for those who has done the tour excursion which use the donkey-drawn rail cart and take you to the cenote or underground cave. This tour is offered through Royal Caribbean it is called "Hidden World Snorkel & Mayan Outback Adventure".

It seems like they offer two choices to get to the underground cave by bicycle or by the donkey-drawn rail cart. On the picture it shows only one donkey cart. My question is, do they have more than one donkey cart? Just wondering if we choose the donkey cart option how long we have to wait for our turn (2 adults 1 child) to get there, how long is the donkey cart ride to the underground cave ?

Thanks

Not sure which cenote they will take you. There is a group of cenotes called Santa Barbara where there are 3 cenotes and the travel between them is by horse/mule-drawn rail platform.