Ride_Op posted on December 15th, 2020
The lift hill automatically stops before the train reaches the top if the block ahead is occupied. If the lift hill keeps going without stopping, it means that the ride knows that the next block is clear, whatever that is. As that train cycles around the track, it inevitably must pass through the block border, which should trigger a warning about multiple trains on the same block. This is what keeps the brakes closed, which then causes the collision.
How to find the issue? Well, you can see where the first train is when the occupied block warning happens. Or in the editor, you can change the comb view to show the blocks. Color coded sections will show you where all of your blocks start and end. If you have things set properly, it will show the same color from the end of the lift segments all the way to the end of the initial brake. If not, where the color changes is your extra block that allows the train to pass over the lift, but doesn't stop the train, which causes the problem.
-Ride_Op
The warning about multiple trains on a block is triggered right as the 2nd train leaves the lift, as the 1st train has not yet reached the initial brake. The lift is not acting as a block. There is one single block from the end of the lift through the end of the initial brake