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Crews prepare for track work on North Metro Rail Line

As we prepare to move into track and system work on the project, there is quite a bit of work that needs to happen beforehand.

Some of this "behind the scenes" work is occurring now on the North Metro Rail Line and includes the installation of various measures to protect the train and surrounding objects from the electricity used to power the train.

Currently, crews are installing arc flash shields on the underside of existing bridges that pass over the North Metro alignment.

The arc flash shield is installed to protect the concrete structures from an arc of electricity generated between the train pantograph (framework mounted to the roof of the train car to collect power) and contact wire as the train passes underneath.

Arc-flash-sheilding-under-bridge
University of Colorado A Line bridge at Colorado Boulevard in Denver

This “arc flashing” refers to the electricity from the Overhead Catenary System (or OCS wires) that run above the rail to power the rail cars. Occasional variances in track and rail height cause the car to lose contact with the wire. A flash of electricity occurs from the wire to the car in the shape of an arc.

To prevent damage to the bridges above from this occasional arc flashing, an aluminum shield is installed directly over the OCS wires. (See above).

Installation of the shield took place in July at Park Avenue and under Interstate 70.

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