More trains does not decrease cycle time. Each train still takes just as long to load, go through the ride and unload; completing the same number of cycles per hour. There is no way to negate loading and unloading.
Assume: 2 minute ride. 2 minutes to unload/reload. Assume you are able to send a second vehicle out once the first hits the block brakes half-way through the ride at the one minute mark.
Then, if you had one and only one train, the train goes around the tracks in two minutes. It spends 2 minutes in loading. Goes out again. 4 minute cycle. With one train, that's one train every 4 minutes.
Then with two trains: First train goes out. When it gets past the first block at the 1 minute mark, second train goes out at the beginning of the second minute. One minute later (the beginning of the 3rd minute), the first train enters stations and begins the 2 minute reload. In the next minute (the fourth) the next train comes in while the first train is reloading. Next minute (the 5th) the first train goes out again, and a minute later the next train. So, every 4 minutes, two trains go out.
Then with three trains: First train goes out. Next minute, the second. Third minute, the third train goes out while the first comes in to unload. In the fourth minute, the first train is now reloading. The first train is not ready to go until the 5th minute. So, every 4 minutes, three trains go out.
Then with four trains: First train goes out. Next minute, the second. Third minute, the third train goes out while the first comes to unload. In the fourth minute, the fourth train goes out while the first is now reloading and the second train is unloading. In the fifth minute, the first train is ready to go out again. Every minute a train leaves the station. In four minutes, 4 trains. A train per minute.
Extra vehicles in the station getting ready to go means there's always a vehicle ready to go whenever it's possible to send the next out.
Think of an omnimover. It is always sending a car out when one arrives. You don't figure in load/unload because it's obvious that the load/unload happens in the station without delaying the sending out of the next vehicle. Same thing for vehicles even when there's a gap in time before sending the next one out, if you have enough extra cars and/or an extra loading station. This way, you can always have a vehicle ready to send out at the next possible opportunity.
Extra vehicles can remove the unload/load time from the cycle equation. (Although, nothing can obviate problems with people who load incorrectly and cause an E-stop.)