I made a functioning train station that features on-demand minecart departures, with a 1-minecart queue.
It's a pretty good tutorial world with:
- On-demand minecart departure gate
- 2 dual-minecart "engines" to power the Departure and Arrivals-to-Departure-Gate systems
- 2 inline boosters for long-distance minecart systems (one in the open, and one embedded in a tunnel)
- demonstration of pressure-plate and switch-activated T-intersections of minecart tracks
1.) Download and extract the .zip file linked below
2.) Rename the 'Worldx' folder to a world # you're not using (i.e.: World3)
3.) Move the new World3 (or whatever) folder to your minecraft saves directory (make sure you can view hidden directories)
XP: C:\Documents and Settings\%username%\Application Data\.minecraft\saves
.zip file: http://download.geeklimit.com/minecraft/minecart_demos/Worldx.zip
A few notes:
ON THE SYSTEM AS A WHOLE
The key to the advancement system (arrivals gate to departures gate) is timing. The arrivals advancement booster needs to leave its holding loop ASAP, but needs to advance the minecart waiting at the Arrivals gate AFTER the departures gate minecart leaves, or the arrivals minecart rear-ends the departures minecart. And the departures minecart doesn't leave until the departures booster pushes it.
Once the departures minecart is launched, both the departures booster and the arrivals advancement booster automatically reset. The 2 stone pressure plates activate both.
This system only works because the arrivals advancement loop is a quick-release and long-delivery system. The departures booster is a slow-release and quick-delivery system. Both are sized relative to each other to keep the arrivals cart from rear-ending the departures cart, which would stall the system.