The "Car Barn" project was originally designed as a simple garage and rail yard for light repairs and storage, with some offices for staff. But it has ballooned in ambition and nearly tripled in cost - to US$48.8 million. It will now include a number of pricey and unusual features, including grass tracks for parking the fleet of six trams and a cistern for washing them with rainwater.
At the same time, a short stretch of track that the city built in Washington's Anacostia neighbourhood, never reached its intended destination and has been all but abandoned, leaving the city with a multimillion-dollar, eight-tenths of a mile monument to good intentions.
Since 2014, operators have been shuttling the bright-red trams back and forth without passengers, each trip underscoring questions about the District's ability to get big things done.
In the early 2000s, an ambitious band of city officials set out to cut through the bureaucratic mire and launch a vast tram network that would be a model for the nation, eventually running 30 to 60km or more.
The first leg was supposed to open in 2006. But as 2015 comes to a close, officials are scrambling towards their latest goal of opening a diminished, 3.5km tram line east of Union Station after the latest tests are finished early next year.
Tram lines have faced challenges across the country. The projects are often designed to spur development as much as to move people. They have sometimes been spearheaded by agencies with minimal experience building or running rail transit systems, leading to rosy assumptions on costs and timelines, comparative studies have found.
But in Washington, the problems have gone deeper. Officials working with a succession of mayors failed to keep a tight handle on the sprawling effort, marked by poor management, hasty designs, construction problems and political infighting, according to internal project documents obtained through public-records requests and interviews with current and former officials.
The peculiarities of streetcar systems - with their local political histories as well as varied costs for real estate and for moving gas and electric lines - make broad comparisons challenging.
But narrower comparisons illuminate deep disparities. Take maintenance facilities. The District says it will spend US$48.8 million on its Car Barn and maintenance yard, which is projected to open in 2017 after long delays. Tucson spent US$13 million. Cincinnati's was US$11.5 million. Seattle's came in at US$11.1 million, plus - at most - US$500,000 for track and overhead wires in the yard, officials there said.

