The big challenge is where the wires of the trolley buses cross the streetcar wires. I observed three such crossovers in the overhead wiring: at Westlake/7th, Westlake/Denny, and Mercer/Fairview. How to keep the two systems apart while avoiding a short circuit and still permit the current collectors to do their job as the vehicle negotiates the crossing? This is accomplished in different ways by the various transit systems throughout the world that have both streetcars and trolley buses. Here is Seattle's solution: a ceramic block with cutouts for the electric trolley bus wires. The trolley bus poles stay attached to the wires through the cutouts. The streetcar pantograph is pushed below the trolley bus wires by a series of metal skids which I presume are not electrically "live". This produces a great shower of sparks as the streetcar traverses the crossover. I need to film a movie of this and post it. I did not observe a trolley bus traversing a crossover, but it is apparent that the bus would need to be aligned directly under the apparatus or the poles would be in danger of hitting the ceramic block and disengaging their wires.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRzliUUJNugw0I89uRQtkxA-Qoxp8vRFbr1ccow87SmMTHUXfWiinDfKf46saQy-AcleyOQVaGcqCaeNRx2WRuTWdgtACxL3IjOsECQZPn_rDv0CffPJftL7LcD_IMMZxgK__O88msgc5M/s400/FairviewMercerSpecialWork1.jpg)
Here are two pictures of the special work at Mercer and Fairview. The route 70 wire intersects the streetcar wire at an oblique angle, not 90 degrees.