A rare four-car Yellow Line / Skokie Swift train of Bombardier-built 5000-series 'L' cars sweeps through Oakton Curve in Skokie. This superelevated curve was famous for decades as the point where North Shore Line interurbans could really "open up" on their runs north over the Skokie Valley Route. The North Shore Line-era catenary supports, still in place after CTA converted the Swift to third-rail operation in 2004, hark back to the era of high-speed interurbans. The four-car sets were being used on the Yellow Line to accommodate equipment in the front of the lead car that spreads an anti-icing solution on the third rail. This, in addition to sleet scrapers ahead of and behind the third-rail shoes, keep ice, snow and sleet from sticking to the conductive rail.