Maryland’s Purple Line has suffered numerous delays and significant cost overruns, and a mezzanine is the latest part of the project to increase in cost.

The planned mezzanine connecting the D.C. Metro‘s Bethesda station and the Maryland Department of Transportation Purple Line’s stop in Bethesda was estimated originally at $2.4 million, but years later, a contract announced for the project was for $52 million, according to a report from the Washington Post.