A Very Tiny Parade

In this photo of a pantograph cart you can see the aluminum test bar on the top of the t-shaped structure. Also note the flanged train wheels on either side of the rubber tires. In order to line up the testing gauges, the cart will be towed along the track on those wheels.

In this photo of a pantograph cart you can see the aluminum test bar on the top of the t-shaped structure. Also note the flanged train wheels on either side of the rubber tires. In order to line up the testing gauges, the cart will be towed along the track on those wheels.

If you love a parade, no matter how small, you will want to station yourself along the First Hill Streetcar route this Saturday. The Seattle Department of Transportation (SDOT) will be testing streetcar elements by pulling a “pantograph cart” along the new streetcar track (we told you it was a small parade). The idea is to replicate streetcar operations as closely as possible in order to make sure everything is functioning properly prior to testing the streetcars on the tracks.

First, what’s a “pantograph”? It is a device mounted on the roof of a streetcar that makes contact with the overhead electric wire and transfers the electricity from the wire to the motors that power the streetcar.

The pantograph cart is a small trailer that has been designed and outfitted to conduct specialized tests of the streetcar track, the overhead electrical system, and structures along the track (such as the station platforms).

To test the overhead wires, the cart has been outfitted with an aluminum test bar the same height and width as the contact bars that will be on our streetcars’ pantographs. The cart will be pulled along the streetcar route at a walking pace, accompanied by project engineers who will monitor the position of the overhead power wire relative to the test bar.

This is an example of the testing gauge being built to replicate the streetcar’s profile, size, and dimensions.

This is an example of the testing gauge being built to replicate the streetcar’s profile, size, and dimensions.

To test the clearance between the cars and the station platforms, a “gauge” has been built that replicates the profile of the train. The gauge is mounted in front of the cart and is made out of aluminum, surrounded by rubber, and affixed to a steel tubular frame.

This is just one of many different tests being conducted prior to the start of streetcar operation. If you are lucky enough to see the pantograph cart in action, snap a photo of it and tweet it to us at twitter.com/TheStreetcar .