horn must be sounded twice when departing a station, at one point where the track parallels the currently unused PeopleMover/Rocket Rod track, and when approaching the Matterhorn. They are also sounded when a bird lands on the track, and as a greeting to passing Disneyland Railroad trains near the switch to the barn. The original monorails were equipped with horns that sounded more like real ground-level trains. Maintenance "Monorail Shop", as it is officially known ("Shop" for short), is Disney's monorail maintenance facility located behind "it's a small world" and I-5 Freeway entrance to Harbor Blvd. at Disneyland and provides space for four monorails on its upper level (the bottom level houses the five steam locomotives that circle Disneyland). Monorails access this yard by stopping at the switch near the road crossing and then the switch will switch to the facility spur. Then the monorail travels slowly into the yard where another switch leads it into the designated track. No train will ever be left outside the facility because routine maintenance is performed nightly. Tractor The diesel/hydraulic powered "work tractors" are primarily used each morning for beam inspection and maintenance-of-way which includes trimming vegetation beyond the reach of guests, cleaning and repairing the electrical commutator rails as well as periodically scheduled servicing and painting of the concrete beam guideway. They are powerful enough to return a fully loaded train fitted with tow-bars to a station platform, then to the Monorail Shop, independent of 600 V track power. Installation and removal In order to remove old monorail trains and replace them with new ones, they are shunted to maintenance shop beam "D" where each car segment is prepared individually for removal by supporting the remaining segment and disconnecting the bellows, cables, and articulated motor truck. The car is then rolled outside along the beam to a position where a custom crane-hoist harness is fitted to it and the car is hoisted off the beam and transferred to a truck trailer on which a transport beam is bolted. The Diesel/hydraulic tractor (pictured) is used as a switcher to carefully tow each car into and out of the maintenance shop. The procedure is reversed for fitting new segments of monorail train cars to the beam while testing each system and connection. Each fully assembled train is then slowly and methodically tested thoroughly over many months before it can be placed into revenue service