In order for you to play Train Valley on macOS with minimal graphics settings, your computer must meet the following requirements
Operating System:
Mac OS X 10.12+
Processor (CPU):
1.7 GHz Intel Core i5
Memory (RAM):
2 MB RAM
Graphics Card:
NVIDIA GeForce 8600M or better / ATi Radeon 2400 or better
Storage:
1 GB available space