Sonoma-Marin Area Rail Transit contractors will close Guerneville Road in west Santa Rosa Friday morning through the weekend in order to replace railroad tracks.

The road will be closed at the tracks from 9 a.m. Friday until 7 p.m. Sunday, SMART said. Routes used for detours include Steele Lane and Marlow Road.

The ongoing work will upgrade the tracks, including all road crossings, from Airport Boulevard north of Santa Rosa to San Rafael to prepare for commuter rail service in late 2016.