Analysis of information sources in references of the Wikipedia article "Semi-metrô" in Portuguese language version.
light rail subway/surface line
descending into tunnels in the style of conventional underground mass transit
... San Francisco and Boston, both with semi-metros and independent plans for new tramcars.
pre-metro: a light rail transit system designed with provisions for easy conversion to rail rapid transit
By this time, there was considerable interest in reconfiguring the U.S. subway-surface streetcar systems to resemble northern European practice, and there was increasing recognition that modern tramways might be appropriate for urban regions that long since had given up streetcar operation.
