Today on Boston Public Radio:

• The MBTA is having a full-on meltdown, with two train derailments taking place over the course of a few days. We opened up the lines and asked listeners: Is it time to raise taxes to fix the beleagured transit system?

• Should children be able to make their own medical decisions about vaccines? Medial ethicist Arthur Caplan weighed in on the ongoing debate.

• Homeland security expert Juliette Kayyem discussed the president’s attempt to block Congress from accessing documents about the 2020 Census citizenship question.

• Boston Globe business columnist Shirley Leung talked about the Raytheon - United Technologies merger.

• Are face scans at airports a privacy trap? Tech writer Andy Ihnatko explained.

• Author and Boston Globe columnist Alex Beam discussed the untimely (or timely?) death of the friendship tree gifted to President Trump from French President Emmanuel Macron.

• Art curator Pedro Alonzo discussed the upcoming public art installation New Horizon, which features a reflective hot air balloon that will travel across Boston.