Need some blueprints of simple working train runs

[gsezz]

Have two trains in the west most blocks and a third in the central block heading west. Deadlock.

Nope. The central block has chain signals on both entries. No train will ever enter the central block if the block behind the center isn't free.

[Jap2.0]

From that screenshot it looks like it should support the 3rd train, maybe even a 4th, then lock up on the 5th as every rail segment would be occupied.

Yep, the 5th would be a deadlock. You might actually be able to create a deadlock with three, but the maximum theoretical capacity is 4.

No, with 3 it won't deadlock, because one of the trains will always be able to advance to the next block, freeing up the block that was previously occupying to another train.

Have two trains in the west most blocks and a third in the central block heading west. Deadlock.

The trains will not cross the chain signal at the exit of the east blocks to go west until it can reserve the standard signal on the entrance of the west block block. If there are two trains in the west blocks, then it will have to wait at the chain signal at the east, leaving the main block free.

Yep, you're right. I missed that. Or temporarily forgot how chain signals work. Or something.