There are twelve monorails at WDW - the current Mark VI monorails, built by Bombardier, started service in 1989. They are stored in the Roundhouse, above the steam trains, behind the MK park. Following the steam train spur off of the Mickey's Toontown station leads to the Roundhouse. That is where all cleaning and servicing is done to the trains.
The colors are Red, Black, Blue, Gold, Silver, Lime, Peach, Orange, Yellow, Green, Purple and Pink.
Any other questions about the Monorails?
-Kim