Today, the upper deck carries six car lanes while the lower deck carries a double track railway, electrified at 25 kV AC. From the late 19th century, there had been proposals to build a bridge across the Tagus.OverviewThe 25 de Abril Bridge is a connecting the city of, capital of, to the municipality of on the left (south) bank of the. It has a main span length of 1,013 metres (3,323 ft),. From the late 19th century, there had been proposals to build a bridge across the Tagus. In 1929, the idea advanced when the Portuguese engineer and entrepreneur, António Bello, requested a government concessio.