Portland Streetcar - Comparison With Light Rail

Comparison With Light Rail

In contrast with light rail transit systems, vehicles on modern streetcar systems such as the Portland Streetcar are rarely separated from other traffic and are not given traffic-signal priority over other vehicles, except in a few situations to allow the rail cars—which cannot turn as sharply as other most motor vehicles—to make some turns. In Portland, using this "mixed traffic" operation has reduced the cost of constructing each segment and—by not closing traffic lanes permanently to other traffic, as is typically done with light rail—also minimized disruption to traffic flow, and allowed curbside parking to be retained, but also means slower operating speeds compared to light rail. Additional factors making the Portland Streetcar line less expensive to build per mile than light rail are that use of city streets largely eliminated the need to acquire private property for portions of the right-of-way, as has been necessary for the region's light rail (MAX) lines, and that the vehicles' smaller size and therefore lighter weight has enabled the use of a "shallower track slab". The latter means that construction of the trackway necessitated excavating to a depth of only 12.2 inches (310 mm) instead of the conventional (for light rail) depth of around 18.3 inches (460 mm), significantly reducing the extent to which previously existing underground utilities had to be relocated to accommodate the trackway.