one way i learned to remember signals is that chain basically means 'don't enter unless you can get out'

"Chain IN, Signal OUT" - basic rule of train signalling. Use a Chain Signal to tell an inbound train if it is safe to enter an intersection. Use a Signal to identify that an outbound train has safely cleared the intersection.

ψ ṯ̶̻̾h̸̥͇̃̀̇̚ḛ̶̪̺͌͆ͅ ̵̠̦̻͊͝f̵̢̭̍̆̐̇ḁ̶͓͌͒̔c̶̘̹̮̦͝͠t̷̥̓ơ̸̫̤̤̿͑̑r̴̢̙̥̦̾͋̄͝ỳ̶̜̱̯̠̚ ̶̹̙̻̣̤̔͠m̷̡̲̱̞̉́̓͗͜ú̷͉̥̩̮ͅs̸͉̯̀͑͂t̸̡̫̙́̎́̐ ̸̪͈̪̀ǵ̵͚̝̬̌͆ŗ̸̱̫̈́͜o̶̭̬͌̾́ẁ̴̝͘͠ ψ
ψ ṯ̶̻̾h̸̥͇̃̀̇̚ḛ̶̪̺͌͆ͅ ̵̠̦̻͊͝f̵̢̭̍̆̐̇ḁ̶͓͌͒̔c̶̘̹̮̦͝͠t̷̥̓ơ̸̫̤̤̿͑̑r̴̢̙̥̦̾͋̄͝ỳ̶̜̱̯̠̚ ̶̹̙̻̣̤̔͠m̷̡̲̱̞̉́̓͗͜ú̷͉̥̩̮ͅs̸͉̯̀͑͂t̸̡̫̙́̎́̐ ̸̪͈̪̀ǵ̵͚̝̬̌͆ŗ̸̱̫̈́͜o̶̭̬͌̾́ẁ̴̝͘͠ ψ
ψ ṯ̶̻̾h̸̥͇̃̀̇̚ḛ̶̪̺͌͆ͅ ̵̠̦̻͊͝f̵̢̭̍̆̐̇ḁ̶͓͌͒̔c̶̘̹̮̦͝͠t̷̥̓ơ̸̫̤̤̿͑̑r̴̢̙̥̦̾͋̄͝ỳ̶̜̱̯̠̚ ̶̹̙̻̣̤̔͠m̷̡̲̱̞̉́̓͗͜ú̷͉̥̩̮ͅs̸͉̯̀͑͂t̸̡̫̙́̎́̐ ̸̪͈̪̀ǵ̵͚̝̬̌͆ŗ̸̱̫̈́͜o̶̭̬͌̾́ẁ̴̝͘͠ ψ

Single Traffic Bulb - request further for exit (put always BEFORE intersection) STB marks the end of way.
Triple Traffic Bulb - receive signals and give permission for enter (put always AFTER intersection) TTB marks the beginnig of way.
To make the rails one-way, only triple traffic bulbs need to be placed correctly!

you star , thank you