Yeah, this is much better. (there is nothing wrong with tunnels). I'm glad you've found interesting solution to the first one. Have fun creating more elaborate layouts...

The real solution is this stamp:
https://gtm.steamproxy.vip/ugc/782992988816056089/BF0AF56D8F6295CFE55103B5F3990059004627F2/?imw=637&imh=358&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=true
It handled the 15 trains with no problems (but it uses tunnels).

It seems like for long enough trains this jam will always be unavoidable, unless I made entrances 3 squares wide (allowing to separate entrance and exit like you marked in green).

Ahh you are right... I will have to keep trying on this one. It did eventually jam:

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1918801822

The test setup has 3 different routes with 5 trains on each route. One route is "hit each sequential station clockwise", the other route is "hit each sequential station counterclockwise", and the last is "hit the stations in a cross pattern". This way the trains behave in a fairly unpredictable manner.

Thanks!

I'm intentionally creating fairly large blocks to facilitate a large train. Also, I tested this with a lot of trains - it performed pretty well.

The one you marked green - yes I'm very aware of that, and the chain pointing left (it's just to the right of the green box) did help a lot (before that there were pileups). Really this needs to be one square wider in X and one square wider in Y, to allow separating the incoming from the outgoing blocks - they are linked and it does slow things down.

I did run this fairly extensively with a test case - I'll post the image.

hello...
You made a typical mistake of "not enought signals" on this stamp.
http://prntscr.com/q0w8ru
The red squares - the signals simply must be there (and on each side of the square, not only on the marked one) for it to work or it simply won't. In mashinky, the tracks are divided into blocks = piece of track between each and every switch and each such block requires signal unless you want to whole side of the large square to be occupied by only a single train (and that defies a purpose of elaborate crossing...)

The green square marks "bad block" = you cannot place signal there and I can pretty much guarantee that sooner or later trains will get stuck there. The solution is to redesign that particular piece in the way where the side line crosses the two main lines at an angle (not perpedicularly) so signal could be placed there.