Homemade Rat Trap Success

I finally caught the rat that was drilling the floor of my barn. Our metal barn is built on a wood foundation resting on gravel. The rats have an easy game drilling tunnels under the wood beams, which weakens the 30 years old beams. They steal food and garden seeds, and leave a mess behind.
I have been trying to catch the rat responsible of this for some time, using a pipe trap. The pipe is resting horizontally on an axis in its center. Once the rat gets in and passed the middle, the pipe then flips vertically, the rats falls in the bottom of the pipe and is stuck there.
That did not work very well. The rat would get in there, fall in the bottom, eat all the bait, and somehow get back out.
Next try was to remove the end cap, and set the pipe above a metal garbage can. Instead of falling in the bottom of the pipe, the rat would fall in the garbage can, and would get stuck there. A foot of water in the garbage can would prevent the rat from jumping back out, and would also drown it, trapped rats can attack you.
After a few unsuccessful trials where the rat would trip the trap and eat the bait, but get away, I finally got him. I actually got two rats at once (which raises the question: how many are they?), and immediately reset the trap. So here is the homemade rat trap:

Click on the image for full size.
The piece of 2x4 at the entrance keeps the pipe in position. Once the rats pass the middle and start moving the pipe, the piece of 2x4 falls, which increases the imbalance and causes the pipe to tilt more rapidly.
Here is the inside of the pipe, with the bait (you can see the piece of 2x4 resting on top of the pipe at the other end):

Here, the pipe after the rats tripped the trap:

Notice how the pipe end just comes to the top of the garbage can, so that the rats slide nicely into it. Here is the graphic result:

I did not expect to catch two at once. They are big with that. Since the pipe does not come back into position after the trap tripped, they were inside the pipe at the same time. Cool catch! So the trap has been reset. I will eventually have a more permanent setup, but for now, this is working well.