Here is a simple push button start gate I made. I will make it look better later.
12 volt door opener solenoid on amazon, you get 2 for $9. Search for Zone Tech 2-Pack Universal High Power Door Lock Actuator.
Fat Track start gate from JLH Krafts https://www.jlhkrafts.com/
The rest is talent and trial and error, thats what you need to provide.
Video of it in action here: