What to Watch on Tuesday: America’s first subway system in Boston

The Race Underground (9 p.m., UNC-TV) – In this American Experience documentary, engineers overcome challenges to construct America’s first subway system in Boston.

Switched at Birth (9 p.m., Freeform) – In the Season 5 premiere, Bay and Daphne rush home from China after they receive an emergency call.

Outsiders (9 p.m., WGN) – A new arrival threatens to disrupt the balance of power on Shay Mountain.

Bones (9 p.m., Fox) – When a tutor who works with privileged students turns up dead, the team sifts through possible murderers.

Frontline: Battle for Iraq (10 p.m., UNC-TV) – A report on the fighting inside Mosul, Iraq, includes comments from civilians, soldiers and ISIS suspects.

Taboo (10 p.m.m, FX) – James Delaney sets out to protect his business by any means necessary.